JavaCompiler : Java Glossary

You don’t use exec or sun.tools.javac.Main any more.

Benefits

• The compiler runs in the same JVM (Java Virtual Machine) as your program. You don’t have the startup overhead of a second JVM.
• The complier stays resident. So when you compile more source files, you don’t have to fire it up from scratch again, the way you do with the command line or exec.
• You can use it to compile code that exists only in RAM (Random Access Memory). You can generate it on the fly, compile it and execute it. This opens up all kinds of new ways of writing code. For example, imagine a spread sheet program that generated a Java program to compute the cells, the compiled it and ran it. It would run just as fast as a hand-written custom program to do those calculations. You can compile Java source that comes to you over a socket.
• JavaCompiler will work with any platform, with any Java compiler. exec hooks have to be tuned to the platform.
• ANT, JSP (Java Server Pages), Hibernate etc. will use this hook. They all need to invoke the compiler repeatedly and efficiently. JSP generates Java source from the mixed HTML-Java source it uses. These tools will no longer have to use illegitimate com.sun.javac. Main back door they are forced to use now.
• Astoundingly, the JavaCompiler API (Application Programming Interface) does not require the JDK (Java Development Kit) to be installed on the client machine. All it needs is the JRE (Java Runtime Environment) with its tools.jar on the classpath or copied into the ext directory.

Sample Code

sun.tools.javac.Main

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