Sun Java WorkShop makes Java development faster and easier and enables you to work on Internet time. With Java WorkShop, you get ease-of-use, visual application development, code reuse and the high performance you need.

Java WorkShop is the ultimate Java development environment - brought to you from the creators of Java.

Java JIT Compiler Overview
In order to understand JITs (Just-in-time Compilers), you must first understand how the Java Virtual Machine (JVM) works. When you write a Java application, such as the following hello world program,

class hello {
public static void main(String argv[]) {
System.out.println("Hello!");
}
}

you first run "javac", the Java Compiler, which turns the Java code into what is known as "bytecodes" and puts them into the "hello.class" file. This class file can then be interpreted on any machine which has a Java Virtual Machine on it. The key word here is "interpreted". The Java Virtual Machine processes each of the bytecodes in the .class file and executes them. This is similar to what other interpreted languages do, such as Basic, LISP and Smalltalk.

When a JIT is present, the Java Virtual Machine does something different. After reading in the .class file for interpretation, it hands the .class file to the JIT. The JIT will take the bytecodes and compile them into native code for the machine that you are running on. It can actually be faster to grab the bytecodes, compile them and run the resulting executable than it is to just interpret them. The JIT is an integral part of the Java Virtual Machine, so you never notice it's there, except your Java runs faster. Some environments allow you to choose whether or not to JIT code.

Java is a dynamic language, so you are not allowed to "statically" compile all the .class files into machine code until they are actually called. Thus the JIT is really "just-in-time", since it compiles methods on a method-by-method basis just before they are called. If you call the same method more than once, the JIT'd code can really pay off as you do not have to re-JIT the method and can simply re-execute the native code.

Does it make sense to always JIT code? No, not always. Sometimes JIT'd code does not run any faster than interpreted code. If the Java Virtual Machine is not spending its time interpreting bytecodes, then JIT'ing the bytecodes will not speed things up. Although it is rare, things might slow down since you are spending the time compiling the bytecodes when you could have been interpreting them.

Sun Java WorkShop v2.0 will incorporate a Java JIT compiler into the development environment. Java WorkShop 2.0 is the next-generation Java IDE that allows developers to design, test, deploy and maintain Java applets, applications and JavaBean components - from dynamic, animated home pages to sophisticated, interactive business applications - with speed and simplicity.