Java Software Development

Remote JMX client

2012-01-03T07:49:00.000-08:00

Add these properties to the target VM to specify the jmx port and allow remote connections so you can get to it from other systems without the need for authentication.

JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.port=9999"

JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.authenticate=false"

JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.ssl=false"

The example below demonstrates the following:

Connection
Listing all MBeans
Listing all MBean attributes, types, and mutability
Listing all MBean operations, parameters, and return types
Getting an attributes current value
Setting an attributes value
Invoking operations


import java.io.IOException;
import java.util.Iterator;
import java.util.Set;

import javax.management.Attribute;
import javax.management.AttributeNotFoundException;
import javax.management.InstanceNotFoundException;
import javax.management.IntrospectionException;
import javax.management.InvalidAttributeValueException;
import javax.management.MBeanAttributeInfo;
import javax.management.MBeanException;
import javax.management.MBeanInfo;
import javax.management.MBeanServerConnection;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import javax.management.ReflectionException;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;

public class MBeanClient
{
 public static void main(String[] args) throws IOException, MalformedObjectNameException, NullPointerException,
     InstanceNotFoundException, ReflectionException, IntrospectionException, AttributeNotFoundException,
     MBeanException, InvalidAttributeValueException
 {
   // Connect to server
   JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://localhost:9999/jmxrmi");
   JMXConnector jmxc = JMXConnectorFactory.connect(url, null);
   MBeanServerConnection mbsc = jmxc.getMBeanServerConnection();

   // List all MBeans
   Set names = mbsc.queryNames(null, null);
   for (Iterator i = names.iterator(); i.hasNext();)
   {
     ObjectName on = (ObjectName) i.next();
     System.out.println("\tObjectName = " + on);
     listAttributes(mbsc, on.getCanonicalName());
     listOperations(mbsc, on.getCanonicalName());
   }

   // get value of SomeAttributeName
   ObjectName someMBeanName = new ObjectName("TopNodeName:subNodeName=Foo,mbeanName=FooBar");
   System.out.println("MaxFileSize: " + mbsc.getAttribute(someMBeanName, "SomeAttributeName"));

   // set value of SomeAttributeName
   mbsc.setAttribute(someMBeanName, new Attribute("SomeAttributeName", 10));

   // get new value of SomeAttributeName
   System.out.println("SomeAttributeName: " + mbsc.getAttribute(someMBeanName, "SomeAttributeName"));

   // invoke operation
   mbsc.invoke(someMBeanName, "someOperationName", null, null);
 }

 private static void listAttributes(MBeanServerConnection mbsc, String canonicalName)
     throws MalformedObjectNameException, NullPointerException, InstanceNotFoundException, IntrospectionException,
     ReflectionException, IOException
 {
   // List all mbean attributes
   ObjectName objectName = new ObjectName(canonicalName);
   MBeanInfo mbeanInfo = mbsc.getMBeanInfo(objectName);
   MBeanAttributeInfo[] attrInfo = mbeanInfo.getAttributes();
   for (MBeanAttributeInfo info: attrInfo)
   {
     System.out.println(info);
   }
 }

 private static void listOperations(MBeanServerConnection mbsc, String canonicalName) throws MalformedObjectNameException, NullPointerException, InstanceNotFoundException, IntrospectionException, ReflectionException, IOException
 {
   ObjectName objectName = new ObjectName(canonicalName);
   MBeanInfo mbeanInfo = mbsc.getMBeanInfo(objectName);
   MBeanOperationInfo[] operInfo = mbeanInfo.getOperations();
   for (MBeanOperationInfo info: operInfo)
   {
     System.out.println(info);
   }
 }
}

Batteries

2011-11-30T09:04:00.001-08:00

CR14505

I2C addressing

2011-11-29T08:52:00.000-08:00

what-i2c-address-should-i-choose

usb_i2c_tech

HOWTO install Flashplayer 11 on Firefox 8 on Ubuntu 10.04 64bit LTS

2011-11-21T12:59:00.000-08:00

Download Flashplayer here

Copy libflashplayer.so to /usr/lib/firefox-8.0/plugins

Create symbolic link: sudo ln -s /usr/lib/firefox-8.0/plugins/libflashplayer.so /usr/lib/firefox-addons

Restart Firefox

Curl Rest Examples:

2011-11-21T06:58:00.000-08:00

GET

curl -X GET -H "Content-Type:application/xml" "http://localhost:8080/some/path/505?username=foo&password=bar"

Create

curl -X PUT -H "Accept: *" -d @someFile.xml "http://localhost:8080/some/path?username=foo&password=bar"

Create or Update

curl -X POST -H "Content-Type:application/xml" -d @someFile.xml "http://localhost:8080/some/path/save?username=foo&password=bar"

Delete

curl -X DELETE -H 'Content-Type:application/xml' -d @someFile.xml "http://localhost:8080/some/path?username=foo&password=bar"

Upload file

curl -X PUT -H 'Content-Type:multipart/form-data' -F "someFile.csv=@someFile.csv;type=text/csv" "http://localhost:8080/some/path/505?username=foo&password=bar" --verbose

Download file

curl -H "Accept: *" "http://localhost:8080/some/path/506?username=foo&password=bar" --O "foo.bar" --verbose

Maven

2011-11-02T08:06:00.001-07:00

Create html dependency report

mvn project-inf-reports:dependencies

Hibernate criteria aliases

2011-10-13T08:59:00.000-07:00

If you create an alias, then create a criteria and join to another table, etc., it is only going to resolve {alias} to the root table that the alias was created for.


hibernateCriteria.createCriteria("orderItems", "i", Criteria.LEFT_JOIN ).add(
    Restrictions.or(Restrictions.sqlRestriction("orderNo=?", orderNo, Hibernate.Long),
    Restrictions.sqlRestriction("{alias}.item_id in (SELECT item_id FROM items WHERE item_id = ?)", itemId, Hibernate.LONG)
                            )
);

Lessons Learnt Blog:


Criteria c = session.createCriteria(BaseTable.class, "base");
Criteria secondCriteria = c.createCriteria("secondTable","second", CriteriaSpecification.LEFT_JOIN);
secondCriteria.add(Restrictions.sqlRestriction("{alias}.id = someCoolCondition");

From the Hibernate docs:

List cats = sess.createCriteria(Cat.class)
.createAlias("kittens", "kt")
.createAlias("mate", "mt")
.add( Restrictions.eqProperty("kt.name", "mt.name") )
.list();

Multiple joins:

The following is a native sql template which has the replaced with a generated alias.


     "EXISTS " + //
     "(SELECT 1 " + //
     " FROM" + //
     "  orderItems <aliasname>" + //
     " WHERE" + //
     "  <aliasname>.orderId = {alias}.id" + //
     "  AND <aliasname>.name='<propertyname>'" + //
     "  AND <otherclause>" + //
     ")";

Linux rfcomm serial communication

2011-09-23T04:18:00.000-07:00

Scan to discover Bluetooth device

Pair with Bluetooth device

Connect with SPP

In one shell/terminal - pipe the input from the Bluetooth device to a file

     cat /dev/rfcomm0 > datalog.txt

In another shell/terminal - echo some command to the Bluetooth device

   echo "8;" > /dev/rfcomm0

Quit the cat command

Inspect the output

     less datalog.txt

Windows Soft Link

2011-09-22T05:19:00.001-07:00

mklink (a windows softlink)

Manifest classpath

2011-09-16T08:01:00.000-07:00

Manifest classpath examples

Message Digest

2011-09-06T12:40:00.000-07:00

MD5 throughput was ~15 GBytes/minute on a quad core Intel i5 @ 2.67GHz running Ubuntu Linux 10.04 and Java(TM) SE Runtime Environment (build 1.6.0_22-b04) Java HotSpot(TM) Server VM (build 17.1-b03, mixed mode)

The throughput was the same whether the digest was computed from bytes on disk or memory.org.apache.commons.codec.digest.DigestUtilsorg.apache.commons.codec.binary.Hex

From file

      String filename = "src/test/resources/somefile";
      is = new FileInputStream(filename);
      assertEquals("bd6b1dc1ac767b018003572a767d2d0d", DigestUtils.md5Hex(is));

Pipe filter stream

      is = new DigestInputStream( new BufferedInputStream(new FileInputStream(filename)), MessageDigest.getInstance("MD5"));

  /*
   * Implementations using DigestInputStream would not need the byte handling as it would be just one filter in a pipe
   * that is being pumped for some other purpose.
   */
      final byte[] buf = new byte[2048];
      while (dis.read(buf) == -1)
      {
      }

      final MessageDigest d = dis.getMessageDigest();
      assertEquals("bd6b1dc1ac767b018003572a767d2d0d", Hex.encodeHexString(d.digest()));

JVM thread dump

2011-05-05T13:01:00.001-07:00

Java options, which lets you direct thread dumps generated via “kill -3” to a file:

-XX:+UnlockDiagnosticVMOptions -XX:+LogVMOutput -XX:LogFile=jvm.log

Pretty cool, but there’s one small catch: the thread dumps still get written to the JVM’s TTY as well as the file.

File Locking

2011-04-29T18:33:00.000-07:00

File locking example

Interviewing developers

2011-04-18T06:33:00.000-07:00

Some developers can't code

Thread dump example

2011-04-12T08:07:00.000-07:00


2011-04-12 09:18:25
Full thread dump OpenJDK 64-Bit Server VM (19.0-b09 mixed mode):

"Attach Listener" daemon prio=10 tid=0x0000000000b0d000 nid=0x33ef waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"DestroyJavaVM" prio=10 tid=0x00007f3a2408d000 nid=0x3391 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"File I/O" prio=10 tid=0x00007f3a2408b800 nid=0x33a2 runnable [0x00007f3a3157e000]
   java.lang.Thread.State: RUNNABLE
 at java.io.FileInputStream.read(Native Method)
 at ThreadDumpTest$4.run(ThreadDumpTest.java:97)
 at java.lang.Thread.run(Thread.java:636)

"Blocked" prio=10 tid=0x00007f3a24081000 nid=0x33a1 waiting for monitor entry [0x00007f3a3167f000]
   java.lang.Thread.State: BLOCKED (on object monitor)
 at ThreadDumpTest$3.run(ThreadDumpTest.java:74)
 - waiting to lock <0x00000007d68b4068> (a java.lang.Object)
 at java.lang.Thread.run(Thread.java:636)

"Blocking" prio=10 tid=0x00007f3a2407f000 nid=0x33a0 in Object.wait() [0x00007f3a31780000]
   java.lang.Thread.State: WAITING (on object monitor)
 at java.lang.Object.wait(Native Method)
 - waiting on <0x00000007d69de280> (a java.lang.Object)
 at java.lang.Object.wait(Object.java:502)
 at ThreadDumpTest$2.run(ThreadDumpTest.java:52)
 - locked <0x00000007d69de280> (a java.lang.Object)
 - locked <0x00000007d68b4068> (a java.lang.Object)
 at java.lang.Thread.run(Thread.java:636)

"Waiting" prio=10 tid=0x00007f3a2407e000 nid=0x339f in Object.wait() [0x00007f3a31881000]
   java.lang.Thread.State: WAITING (on object monitor)
 at java.lang.Object.wait(Native Method)
 - waiting on <0x00000007d693ee00> (a java.lang.Object)
 at java.lang.Object.wait(Object.java:502)
 at ThreadDumpTest$1.run(ThreadDumpTest.java:26)
 - locked <0x00000007d693ee00> (a java.lang.Object)
 at java.lang.Thread.run(Thread.java:636)

"Low Memory Detector" daemon prio=10 tid=0x00007f3a24001000 nid=0x339d runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"CompilerThread1" daemon prio=10 tid=0x0000000000b93000 nid=0x339c waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"CompilerThread0" daemon prio=10 tid=0x0000000000b90000 nid=0x339b waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" daemon prio=10 tid=0x0000000000b8e800 nid=0x339a runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Finalizer" daemon prio=10 tid=0x0000000000b6f000 nid=0x3398 in Object.wait() [0x00007f3a31dc5000]
   java.lang.Thread.State: WAITING (on object monitor)
 at java.lang.Object.wait(Native Method)
 - waiting on <0x00000007d6801310> (a java.lang.ref.ReferenceQueue$Lock)
 at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:133)
 - locked <0x00000007d6801310> (a java.lang.ref.ReferenceQueue$Lock)
 at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:149)
 at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:177)

"Reference Handler" daemon prio=10 tid=0x0000000000b67800 nid=0x3397 in Object.wait() [0x00007f3a31ec6000]
   java.lang.Thread.State: WAITING (on object monitor)
 at java.lang.Object.wait(Native Method)
 - waiting on <0x00000007d68011e8> (a java.lang.ref.Reference$Lock)
 at java.lang.Object.wait(Object.java:502)
 at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)
 - locked <0x00000007d68011e8> (a java.lang.ref.Reference$Lock)

"VM Thread" prio=10 tid=0x0000000000b60800 nid=0x3396 runnable 

"GC task thread#0 (ParallelGC)" prio=10 tid=0x0000000000b03000 nid=0x3392 runnable 

"GC task thread#1 (ParallelGC)" prio=10 tid=0x0000000000b05000 nid=0x3393 runnable 

"GC task thread#2 (ParallelGC)" prio=10 tid=0x0000000000b07000 nid=0x3394 runnable 

"GC task thread#3 (ParallelGC)" prio=10 tid=0x0000000000b08800 nid=0x3395 runnable 

"VM Periodic Task Thread" prio=10 tid=0x00007f3a2400c000 nid=0x339e waiting on condition 

JNI global references: 869


import java.io.FileInputStream;
import java.util.concurrent.atomic.AtomicInteger;

public class ThreadDumpTest
{
  static final Object o = new Object();

  /**
   * @param args
   */
  public static void main(String[] args)
  {
    new Thread(new Runnable()
      {
        @Override
        public void run()
        {
          Thread.currentThread().setName("Waiting");
          // Waiting
          try
          {
            System.out.println("Waiting");
            Object x = new Object();
            synchronized (x)
            {
              x.wait();              
            }
          }
          catch (InterruptedException e)
          {
            e.printStackTrace();
          }
          System.out.println("Finished waiting");
        }
      }).start();

    new Thread(new Runnable()
      {
        @Override
        public void run()
        {
          Thread.currentThread().setName("Blocking");
          // Blocking
          synchronized (o)
          {
            try
            {
              System.out.println("Blocking");
              Object x = new Object();
              synchronized (x)
              {
                x.wait();              
              }
            }
            catch (InterruptedException e)
            {
              e.printStackTrace();
            }
            System.out.println("Finished blocking");
          }
        }
      }).start();

    new Thread(new Runnable()
      {
        @Override
        public void run()
        {
          Thread.currentThread().setName("Blocked");
          // Blocked
          System.out.println("Getting blocked");
          synchronized (o)
          {
            System.out.println(Thread.currentThread().getName() + ": should have been blocked");
          }
        }
      }).start();

    new Thread(new Runnable()
      {
        final AtomicInteger sum = new AtomicInteger();

        @Override
        public void run()
        {
          // File I/O
          Thread.currentThread().setName("File I/O");
          FileInputStream fis;
          try
          {
            fis = new FileInputStream("/home/tcollinsworth/Desktop/elekta-crash-1/jboss-elekta-1.trace");
            System.out.println("Reading file");
            int inByte = 0;
            do
            {
              sum.addAndGet(inByte);
              inByte = fis.read();
            }
            while (inByte != -1);
            System.out.println("Finished reading file");
          }
          catch (Exception e)
          {
            e.printStackTrace();
          }
        }
      }).start();
  }
}

Oracle find all constraints

2011-03-30T08:40:00.001-07:00

Find all cascade constraints


SELECT 
 lc.table_name loc_table,
 lc.constraint_name loc_cons,
 ln.column_name loc_col,
 lc.r_constraint_name rem_cons,
 rc.table_name rem_table, 
 rn.column_name rem_column,
 lc.status,
 lc.delete_rule,
 lc.deferrable,
 lc.deferred,
 lc.validated
FROM 
 user_cons_columns ln,
 user_cons_columns rn,
 user_constraints lc
INNER JOIN 
 user_constraints rc ON lc.r_constraint_name = rc.constraint_name 
WHERE
 (rc.table_name IN ('TABLE_NAME')
 OR lc.table_name IN ('TABLE_NAME'))
 AND ln.constraint_name = lc.constraint_name
 AND rn.constraint_name = rc.constraint_name
ORDER BY lc.table_name;

Oracle data pump

2011-03-28T12:10:00.000-07:00

Export:


1. Ensure that a directory is setup for the data pump in oracle
  a. Create the directory on the physical system
  b. Login via SQLPlus as a dba account
   i. CREATE DIRECTORY <friendly_name> AS ‘/path/to/dump/dir’;
   ii. commit;
   iii. GRANT READ, WRITE ON DIRECTORY <friendly_name> to <schema_user>
   iv. commit;
2. Run the export
  a. expdp username/password<@SCHEMA> DUMPFILE=<output_filename.dmp> LOGFILE=<logfile.log> DIRECTORY=<friendly_name>

Import:


1. Ensure that a directory is setup for the data pump in oracle
  a. Create the directory on the physical system
  b. Login via SQLPlus as a dba account
   i. CREATE DIRECTORY <friendly_name> AS ‘/path/to/dump/dir’;
   ii. commit;
   iii. GRANT READ, WRITE ON DIRECTORY <friendly_name> to <schema_user>
   iv. commit;
2. Run the import
  a. impdp username/password<@SCHEMA> DUMPFILE=<input_filename.dmp> LOGFILE=<import_log.log> DIRECTORY=<friendly_name> TRANSFORM=OID:N REMAP_SCHEMA=<Source_Schema>:<Destination_Schema>
  b. NOTE: the REMAP_SCHEMA is only needed if changing the schema names between source and destination.
3. Recompile any remaining invalid objects

DataScienceToolkit

2011-03-25T07:17:00.000-07:00

CataScienceToolkit

A collection of the best open data sets and open-source tools for data science, wrapped in an easy-to-use REST/JSON API with command line, Python and Javascript interfaces. Available as a self-contained VM or EC2 AMI that you can deploy yourself.

It's essentially a specialized Linux distribution, with a lot of useful data software pre-installed and exposing a simple interface. For full documentation, see http://www.datasciencetoolkit.org/developerdocs.

FlyCam

2011-03-23T12:37:00.001-07:00

FlyCam

Kinect your internet of things

2011-03-22T10:47:00.001-07:00

How the world will interact with things in the future

Universal text editor

2011-01-31T11:55:00.001-08:00

Sublime Text

Code rewrite

2011-01-26T08:49:00.000-08:00

Hacher News post

Joel on software

PCBs

2010-11-24T16:38:00.001-08:00

Silver Circuits

Screaming Circuits - PCB + Assembly

UltimatePCB - PCB + Assembly

Hibernate mapping

2010-11-18T08:49:00.001-08:00

one -> many inverse

Java XML manipulation

2010-10-21T07:50:00.001-07:00

http://www.petefreitag.com/item/445.cfm

Probabalistic classification

2010-10-05T09:42:00.000-07:00

Naive Bayes classifier

You're a bad programmer embrace it

2010-10-04T11:12:00.000-07:00

article

FCC testing costs and process

2010-10-02T18:09:00.000-07:00

knowledgebase

~$5000 for FCC, Canada and European is extra, but not double

Takes less than 30 days, ~1 week depending on backlog

Arduino derivatives

2010-09-27T07:46:00.000-07:00

Boarduino
RBBB
FIO
Teensy <- this is it
Freeduino
Sanguino
Illuminato Parallel
Seeeduino
Seeeduino Mega

hackaday
seeddstudio
engadget
instructables

Ubuntu mount smb drive

2010-09-21T13:36:00.000-07:00

HOWTO persistent
HOWTO manual

sudo apt-get install smbfs

Example:

create .smbcredentials file with:
username=
password=
domain=

chmod 600 .smbcredentials

In fstab create and entry like:

#rochester nas
//roc-nas.foo.com/pathname /media/roc-nas cifs credentials=/home/username/.smbcredentials,dirmode=0777,file_mode=0777,iocharset=utf8,codepage=cp850,unicode 0 0

To mount:
sudo mount /media/mount-name
or
sudo mount -a

To unmount:
sudo umount /media/mount-name
or
sudo umount -a

MOSFETs

2010-09-15T18:55:00.000-07:00

tutorial

Dynamic SQL Oracle PL/SQL

2010-09-15T10:13:00.000-07:00

Examples

Arduino MMC / SD card read/write

2010-09-13T17:07:00.000-07:00

roland-riegel lib

It includes

* low-level MMC, SD and SDHC read/write routines
* partition table support
* a simple FAT16/FAT32 read/write implementation

Seeeduino

Raw and Fat16

HOWTO

Detailed description

Bluetooth 3.0, WiFi combo chip BMC4325

2010-09-10T18:32:00.000-07:00

Broadcom BMC4325 announcement

Android

2010-09-10T17:30:00.001-07:00

Android files

Common tasks HowTo

Binding a List to a data cursor

icon sizes and design
Android icon examples
or on local drive: android-sdk-linux_86/platforms/android-8/data/res

Hierarchy Viewer
layoutopt tool
Layout Objects
Example Views
R.Stylable class
RelativeLayout example
Android graphical widget guide
Tab examples
Table example
Table example w/divider
Table row lines hack
Table rounded border
Table rounded border example 2
WebView - show simple content within an Activity

Service

Manifest service element

Message

Notification

Intent guide
Intent
Intent example

Security permissions
A feature can be protected by at most one permission.

Data storage
Shared Preferences
     Store private primitive data in key-value pairs.
Internal Storage
     Store private data on the device memory.
External Storage
     Store public data on the shared external storage.
SQLite Databases
     Store structured data in a private database.

Content providers
Must be implemented thread-safe.
Call ContentResolver.notifyChange() to notify listeners when data changes.

Strongly recommended that content providers implement fine-grained URI permissions and declare that they support it through the android:grantUriPermissions attribute or

Application location
Specified in manifest with android:installLocation
The default is internalOnly, set to to auto to allow external installation and the user to move it.

Don't use android:maxSdkVersion, it is not necessary.

Memory leaks typically: keeping a long-lived reference to a Context
if you leak the Context, you leak a lot of memory. Leaking an entire activity can be really easy if you're not careful.

For Input Method Framework (IMF): The most important thing for an application to do is to use the new android:inputType attribute on each EditText.

Threading
The main thread is the UI thread, all UI updates must be on the main thread.
Use AsyncTask to perform background operations and callback to update UI thread when completed without having to manipulate threads and/or handlers.

Thread and Handler example

Instead of doing intensive tasks via child threads (as the life of a BroadcastReceiver is short), your application should start a Service if a potentially long running action needs to be taken in response to an Intent broadcast. As a side note, you should also avoid starting an Activity from an Intent Receiver, as it will spawn a new screen that will steal focus from whatever application the user is currently has running. If your application has something to show the user in response to an Intent broadcast, it should do so using the Notification Manager.

Use existing styles and themes - blend in.

Conserver battery power

Hide window title bar
requestWindowFeature(Window.FEATURE_NO_TITLE);

Notification example:


        Notification notification = new Notification(R.drawable.daisy_48px_0, "daisy", System.currentTimeMillis());
        PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, BackgroundService.class), 0);
        CharSequence test = getText(R.string.hello);
        notification.setLatestEventInfo(this, getText(R.string.hello), test, contentIntent);
        
        NotificationManager nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
        nm.notify(R.string.hello, notification);

Launch web page from textview link:

autolink, setMovementMethod, non-HTML
Four ways
Simple text link

J2SE Bluetooth

2010-09-09T13:22:00.000-07:00

HOWTO

StackOverflow

JSR-82 Discovery

Oracle HOWTO include SPP rfcomm example

C/C++ stuff

2010-09-06T07:48:00.000-07:00

typedef

J2ME bluetooth JSR-82

2010-09-05T14:22:00.001-07:00

HOWTO

Java.net Getting Started

Sensors

2010-09-03T13:13:00.000-07:00

FSR
FSR HowTo

VBox image keeps growing and running out of space

2010-09-03T10:55:00.000-07:00

Clean it up
Zero it
Shut it down
Compact it

download SDelete

sdelete -c c:

shutdown the guest OS and virtualbox

vditool SHRINK whatever.vdi

Regex

2010-09-01T13:07:00.001-07:00

Dot does not match new line.

Add one of the following to the pattern to support new line:

(?m) multiline
(?s) dot all

Micro platforms and comm

2010-08-31T05:56:00.000-07:00

Hardware
EcoWizard
FLEX Mini
MICAz
Iris Mote
NeoMote
Sun SPOT

Communications
ANT
6LoWPAN
DASH7
ONE-NET
ZigBee
Z-Wave
Wibree
WirelessHART

Arduino

2010-08-29T18:47:00.000-07:00

On linux

/usr/share/arduino
/usr/share/doc/arduino

/usr/share/arduino/libraries

To install Messenger:

download it
sudo file-roller
open it and navigate to /messenger/arduino/Messenger in the zip
extract to /usr/share/arduino/libraries/

Arduino 0019 current rc1 has String object
currently Arduino GA is 0018

ATMega8U2 USB

OptiBootLoader faster

Arduino as a programmer

Wireless technologies

2010-08-23T17:22:00.001-07:00

Wifi 802.11 $44, 100Mb, 100M

WiFly $44, 100Mb, 100M

SHDC memory with WIFI $50

ZigBee 802.15.4 $20, 250 kb, 100M - 1 mile
Bluetooth 802.15.1 < $20, 3Mb, 100M
Cellular $64 + sevice

2G, 3G
GSM, GPRS, EDGE, W-CDMA, UMTS, TDMA, CDMA, CDMA2000 1xRTT, CDMA2000 1xEV-DO, and CDMA2000 1xEV-DV

4G
must have target peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility

AVR

2010-08-23T13:38:00.001-07:00

AVR site

ATmega1284P summary spec sheet

Android resources

2010-08-22T17:03:00.001-07:00

See Accessing Resources in Code

If all you require is the ability to read raw data (such as a video or audio file), then save the file in the res/raw/ directory and read a stream of bytes using openRawResource().

get an instance of Resources with Context.getResources()

never modify the R.java file by hand—it is generated by the aapt tool when your project is compiled.

ViewGroup = layout

View = widge: button, checkbox, etc.

Fast Arduino servo response

2010-08-22T09:02:00.000-07:00

HOWTO

On Duemilanove board powered exclusively from USB, the power drops out with the servo powered from the board +5V. Need external power for servos!

1 Orange = PWM
2 Red = +5V
3 Brown = Gnd


+--
|1 \
|2  |
|3 /
+--

Android widgets

2010-08-21T23:08:00.001-07:00

Horizontal Slider

Android video capture

2010-08-20T21:28:00.000-07:00

slashdot

Android Camera

2010-08-20T21:21:00.001-07:00

Take picture

Take and save picture

Bluetooth, Wifi interference

2010-08-19T14:14:00.000-07:00

Sharing 2.4 GHz band

Bluetooth interferes with Wifi typically less than 25%

Cisco 20 myths

old but simple explanation of the interference issue

bluetooth access points

Business Models

2010-08-18T15:07:00.000-07:00

Revenue Development

The Case Against Free

Free! Why $0 is the Future of Business

Viral Video Strategies

Sales Complexity

Android sensors

2010-08-18T08:50:00.000-07:00

Orientation
Diagram

getOrientation

Arduino programmer

2010-08-17T23:14:00.000-07:00

located in /usr/shar/arduino
preferences ~/.arduino/preferences.txt

To dump all communication during loading set:
upload.verbose=true

AvrDude

2010-08-17T22:41:00.000-07:00

Can program AVR chips via serial from file.

AVRDUDE can be used effectively via the command line to read or write all chip memory types (eeprom, flash, fuse bits, lock bits, signature bytes) or via an interactive (terminal) mode. Using AVRDUDE from the command line works well for programming the entire memory of the chip from the contents of a file, while interactive mode is useful for exploring memory contents, modifying individual bytes of eeprom, programming fuse/lock bits, etc.

AVRDUDE tutorial

Some info on uploading on the Eclipse page

Reset Circuit

2010-08-16T22:32:00.000-07:00

Schematic

Ubuntu Bluetooth pairing

2010-08-14T16:37:00.000-07:00

FireFly Linux gtkterm

gtkterm -p /dev/rfcomm0 -s 115200

---------------------------

Open System -> Preferences -> Bluetooth Manager
Adapter -> Search - be sure remote is discoverable
Device -> Pair - accept and confirm
Can send files, must confirm on remote end

-----------------------------

To connect RN-41 connect USB
Applications -> Accessories -> Serial port terminal
Configuration -> Port
select /dev/ttyUSBx, 115200, 8,N,1
select local echo
Enter $$$ to enter command mode on RN-41 should return OK

-----------------------------

Open terminal and enter:
sudo getty 115200 /dev/rfcomm0

-----------------------------

In Bluetooth Manager select RN-41 device
Right click and select SPP - should connect

In Serial port terminal turn off local echo and hit Enter - should see login screen

------------------------------

Haven't found command line howto

hcitool scan
sudo hcitool cc 00:06:66:05:04:62
then right click and pair with pin
then right click and select SPP

/dev/rfcomm0 stdout/in
bash> exec > filename < filename
tail -f /dev/rfcomm0
echo "some text to bluetooth" > /dev/rfcomm0

sudo getty 115200 /dev/rfcomm0
opens terminal on bluetooth

/etc/bluetooth/rfcomm.conf

rfcomm -a - to see all devices

/dev/rfcomm0

/etc/init.d/bluetooth

Bluetooth pairing command line

if I do above and
sudo hcitool cc 00:06:66:05:04:62 --role=s
Connects and disconnects, probably missing passkey-agent
seems bluez-pin not in repositories
sudo apt-get install bluez-utils bluez-pin

BluetoothDialup
ubuntuforums
spiration

Android Arduino toolkit/library

2010-08-14T15:29:00.000-07:00

Amarino

Arduino memory

2010-08-10T19:24:00.000-07:00

Practical Arduino pg 365

Arduino IDE Ubuntu

2010-08-09T15:47:00.000-07:00

Arduino playground

sudo add-apt-repository ppa:arduino-ubuntu-team

sudo apt-get update

sudo apt-get install arduino

Ubuntu serial port

2010-08-09T13:25:00.000-07:00

Download GUI Serial Port Terminal
or
Command line minicom

list connections:

dmesg | grep tty

Sensors

2010-08-07T02:56:00.001-07:00

Current

Arduino Bluetooth

2010-08-05T20:05:00.000-07:00

HOWTO

uControllers

2010-08-05T16:37:00.000-07:00

ATmega328P

Robotics

2010-08-02T16:28:00.001-07:00

Robot Marketplace

Cheap servos

Remote control

2010-08-02T14:50:00.000-07:00

Engadget
Gizmodo

SparkFun Ardunio and sensors $20-150
TINI $109
BasicStamp $60-100

Sensors

Bluetooth sensor project

2010-07-20T17:49:00.000-07:00

Java bluetooth API
Java bluetooth API part 2

Java Bluetooth library

Bluetooth sensor project

Bluetooth serial adapter

USB Bluetooth adapter $17.95

USB Bluetooth adapter $8.99

BlueTooth RFID reader

Bluetooth Ardunio board

Bluetooth Mate and bluetooth command set and specs

Class 2 $18.95
Class 2 $21.50

Ubuntu 9.10 partitioning issues

2010-07-18T18:59:00.001-07:00

Can't manipulate partitions.

FATAL ERROR: Bad logical partition 6: enlarged logical partitions overlap

Was trying to fix grub2

Was able to resolve it by rebooting and deleting one partition, then unable to delete the next, but after rebooting could delete one more. Continued until they were all removed, then recreated them.

Bloom filter for key value storage

2010-07-15T12:37:00.000-07:00

bloom filter provides quicker resolution for key value storage

used by google big table

Technology choices

2010-07-14T14:39:00.000-07:00

Okta - Building your house on a rock

Java -> eye on Scala
Tomcat
JQuery
Spring
Hibernate
MySQL
Cloud IAAS

Muti-Tenancy high up in the application

Ubuntu automate display settings

2010-07-12T07:18:00.000-07:00

HOWTO

/etc/X11/xorg.conf

xrandr --output DFP1 --mode 1280x768
xrandr --output DFP_EXTTMDS --mode 1776x1000

left 1280x768
right 1776x1000

Virtual 3200 1091

xrandr --output DFP1 --mode 1280x1024
xrandr --output DFP_EXTTMDS --mode 1920x1080

left 1280x1024
right 1920x1080

Ubuntu 10.04 64 Flash player

2010-07-08T10:46:00.001-07:00

HOWTO

Android as uController

2010-07-08T08:36:00.000-07:00

Serial cable

Android - ardunio robot

Compiz Fusion

2010-07-06T14:22:00.000-07:00

Scale plugin shows all windows on single screen for selection and then takes you to the appropriate desktop showing the window.

Performance

2010-06-29T07:11:00.000-07:00

Ubuntu 9.10 ext4 copy disk->disk
~22-29MB/sec
~25MB/sec avg
~1.4GB/min
~10min to copy 14GB

Java DNS cache

2010-06-28T19:58:00.000-07:00

Replace Java DNS with dnsjava

Prior to Java 6 DNS resolutions were cached forever.

Defaults: Java 6 DNS positive responses are cached for 30 seconds and negative responses for 10 seconds

-Dsun.net.inetaddr.ttl=3600

By default, when a security manager is installed, in order to protect against DNS spoofing attacks, the result of positive host name resolutions are cached forever. When a security manager is not installed, the default behavior is to cache entries for a finite (implementation dependent) period of time. The result of unsuccessful host name resolution is cached for a very short period of time (10 seconds) to improve performance.

HTML and CSS

2010-06-19T11:10:00.000-07:00

div and span

Adobe Reader Install - Ubuntu

2010-06-13T09:44:00.000-07:00

HOWTO

JBoss

2010-06-09T07:34:00.000-07:00

Scan rate to detect changes, i.e., jsp

<JBOSS-INSTALL_DIR>\server\<server config>\conf\jboss-service.xml


<attribute name="ScanPeriod">5000

JNDI testing

2010-06-02T18:21:00.000-07:00

OOC-JNDI

Trillion node network

2010-06-01T08:59:00.000-07:00

Trillions video
trillion node network
scalability - no central authorities (registration, namespaces, ontologies)
no device individual attention
tracktability size can't increase complexity
comprehensiveness

bit, byte, name/value

Internet of Things

JBoss SecurityManager

2010-05-28T08:40:00.000-07:00

Secure Coding Guidelines - see section 6 for how security is checked

JBoss classloding

JBoss SecurityManager HOWTO

Class.getProtectionDomain().getPermissions()

Discovering an apps security requirements

Policy

Security and Permissions

Classes, Methods, and Permissions

Prevent Thread creation

Oracle

2010-05-20T11:22:00.000-07:00

Reduce I/O with cluster tables
Tuning Disk I/O

Monitoring I/O
select * from gv$sysstat where name like '%IO%'

HOWTO

Tuning FAQ

Disk I/O

Jetty

2010-05-19T17:16:00.001-07:00

JAX-WS with Jetty

NTFS Links

2010-05-19T14:42:00.001-07:00

HOWTO

Symmetric key encryption

2010-05-18T17:42:00.001-07:00

HOWTO

Flash Flex

2010-05-18T12:59:00.000-07:00

Adobe Flash Builder 4

DualPanel reversible component

Google Protocol Buffer, ASN.1, COM, CORBA, Thrift, etc.

2010-05-17T18:15:00.000-07:00

Google Protocol Buffers FAQ Interchange vs. RPC

Why not XML

NIO

2010-05-16T18:07:00.000-07:00

Server/Client examples

Getting Started with NIO

NIO don't need a thread per connection with all threads waiting for something to happen

Java 1.4, 5, 6 introduction

Firewall hole punching UDP

2010-05-15T18:16:00.000-07:00

How to punch a hole in a firewall for UDP

UDP code examples

wikipedia

Session Traversal Utilities for NAT (STUN)
Interactive Connectivity Establishment (ICE)

jSTUN

Ubuntu remote desktop slow

2010-05-15T07:57:00.001-07:00

Super fast remote desktop NoMachine protocol

Ubuntu 9.10 HOWTO

FreeNX HOWTO

Java threads out of memory native threads

2010-05-13T06:10:00.000-07:00

Increasing heap can exacerbate the problem

JBoss EE Dynamic Web App

2010-05-12T18:18:00.000-07:00

Tutorial

war-less development with jetty

2010-05-09T13:20:00.000-07:00

Maven Jetty Plugin HOWTO
Maven Jetty Plugin mvn jetty:run-exploded mojo

Deploying a webapp to jetty

HOWTO

Caching, Distributed Caching, Replication, JGroups

2010-05-08T11:42:00.000-07:00

Articles

Use temp table instead of large IN clause for performance

2010-05-06T08:59:00.000-07:00

Oracle limits to 1000 entries in an IN clause

Some queries run faster joining to temp table

Resizing a VBox virtual disk

2010-05-05T06:06:00.001-07:00

HOWTO

Dynamically set log4j level

2010-05-04T08:36:00.001-07:00

logLevel = Logger.getLogger(Fubar.class).getLevel();
Logger.getLogger(Fubar.class).setLevel(Level.FATAL);

Oracle statistics

2010-04-30T15:20:00.001-07:00

EXEC DBMS_UTILITY.analyze_schema('schema_name','COMPUTE')

ANALYZE cluster clusterName compute statistics;
ANALYZE table tableName {compute|estimate|delete) statistics options
ANALYZE index indexName {compute|estimate|delete) statistics options
ANALYZE cluster clusterName {compute|estimate|delete) statistics options

Ubuntu xrdp

2010-04-28T12:15:00.000-07:00

HOWTO