Java Review: Tuesday, October 12, 2011

Java Run-time Exceptions

http://download.oracle.com/javase/1.4.2/docs/api/java/lang/IllegalStateException.html

• Class IllegalStateException
• example
• throw new IllegalStateException();
• use to catch programming development errors.
• exception should never occur unless there is a programming error.

http://download.oracle.com/javase/tutorial/essential/exceptions/throwing.html

• tutorial

http://download.oracle.com/javase/1.4.2/docs/api/java/lang/RuntimeException.html

• Class RuntimeException
• not checked
• not extra code
• danger of being a 'lazy programmer'

http://download.oracle.com/javase/tutorial/essential/exceptions/runtime.html

• can use to side step catch and specify requirements
• Runtime exceptions represent problems that are the result of programming problems
• If the client can reasonable be expected to recover from an exception, make it a checked exception

Garbage Collection in Java VMs

http://terracotta.org/products/bigmemory?asrc=eliminate-java-gc-tuning-2-gc-sno&gclid=CKzY28G346sCFcPt7Qod4kU9Rg

• Big memory
• works with
• JVMs
• HotSpot
• IBM JDK
• JRockit
• what about Dalvik?
• off-heap store
• not subject to Java GC
• Terracotta's tiered cache
• Enterprise Ehcache
• store up to a terabyte in the off-heap

http://www.koushikdutta.com/2009/01/dalvik-vs-mono.html

• Dalvik vs Mono

http://stackoverflow.com/questions/3078301/dalvik-memory-allocation-how-to-change-the-default-limits

• heap-limits set by OEM with Dalvik

http://pallergabor.uw.hu/androidblog/dalvik_opcodes.html

• Dalvik opcodes

http://mylifewithandroid.blogspot.com/2008/12/dalvik-opcodes.html

• DEX file format

http://mylifewithandroid.blogspot.com/2009/12/understanding-dalvik-bytecode-with.html

• Dalvik bytecode and Dedexer tool

http://en.wikipedia.org/wiki/Java_Virtual_Machine

• overview of Java VM

http://ryanolson.wordpress.com/2010/07/13/test-how-changing-the-max-amount-of-memory-per-vm-heap-can-effect-your-rom-cyanogen/

• Cyanogen allow Dalvik VM settings to be modified

http://blog.javia.org/android-allocation-free-code-avoids-the-gc-freeze/

• allocation-free code to avoid GC freeze

http://developer.android.com/guide/practices/design/performance.html

• Android, designing from performance

http://www.xinotes.org/notes/note/1449/

• heap size can be change in 'dx'
• example of changing

http://stackoverflow.com/questions/2298784/determine-when-the-android-gc-runs

• code to see the android GC run

http://stackoverflow.com/questions/1521317/is-it-possible-to-call-gc-in-android

• requesting GC
• System.gc();
• no guarantee it will run

Java Constants and Conditional Compile

http://www.javaworld.com/javaworld/javatips/jw-javatip5.html

• No textual preprocessor
• constants and conditional compilation
• use public static final boolean constant for  a regular if statement in regular code
• Have class using the constant interface implement the constant interface