Java performance and optimization - Size

How to reduce the size of your .class files?

Here is a list of tips.

• Don't initialize big arrays
  
  Compiler doesn't perform any optimization. This example shows that the compiler inserts one element at a time. This becomes critical when the size of the array is big.
  
  String [] a={"1","2","3","4","5"};
     00000000 bipush 9
     00000002 anewarray java/lang/String
     00000005 dup
     00000006 iconst_0
     00000007 ldc "1"
     00000009 aastore
     0000000a dup
     0000000b iconst_1
     0000000c ldc "2"
     0000000e aastore
     0000000f dup
     00000010 iconst_2
     00000011 ldc "3"
     00000013 aastore
     00000014 dup
     00000015 iconst_3
     00000016 ldc "4"
     00000018 aastore
     00000019 dup
     0000001a iconst_4
     0000001b ldc "5"
     0000001d aastore

• Use obfuscators to reduce your class variables names and to remove debugging information

• Use JAR files or
  Jar files are stored in the ZIP file format. You can create them using the jar tool included with the JDK 1.1.

This page was last updated 06 March 1998