Java Bytecode is executable code which is produced by compiling Java Programming Language source code. The output of the compiler is called bytecode, and it is compact, object oriented, multi-tasking program code that can be run unchanged on a number of execution environments called Java Virtual Machines (JVM) on different types of computers. Because bytecode is a well understood format, it may be developed using any number of commercially and/or freely available Java language development environments including: WebGain's Visual Cafe™, Borland's JBuilder™, and IBM's VisualAge for Java™, or Sun's JDK.

• It is technically outstanding.
• There is an ever increasing number of Java language programmers, with more momentum than perhaps C/C++ and Visual Basic.
• Compilers produce bytecode about 100 times faster than C/C++ can be compiled, so productivity is enhanced.
• Our customers can pick their development tools from several different suppliers.
• It is a good foundation on which to base other languages for factory automation.

There are at least two additional ways that Java bytecodes can be generated:

A Java source code generator is a program that automatically writes Java language source code. Today you may choose from an incredibly rich supply of third party tools. See TV Object's Applet Designer if you want to use Visual Basic. Automatic Java source code generation is getting a lot of attention and this means an ever improving menu of choices.

Special editors or compilers can automatically generate Java bytecodes using any appropriate paradigm or language.

To embellish SoftPLC applications, you can do parts or the entire control program in bytecode. SoftPLC Corporation. views the Java language as a superior alternative to Structured Text, an IEC-1131 specified language. The Java language is similar to C/C++ syntax and is object oriented, whereas Structured Text follows a Pascal like syntax and is not object oriented. Java language has a larger following than Pascal now or Structured Text ever will. The rich data types within Java language closely parallel those identified within the IEC-1131 standard.

Multi-threading is supported. Ladder programs can call bytecode subroutines on the same SoftPLC. Using Remote Method Invocation, other nodes can call bytecode subroutines on SoftPLC. Additionally, other nodes can freely use our pure Java RemoteDataTable class. "Other nodes" can be any type of computer for which there is a TCP/IP enabled JVM, including mainframes.

• SoftPLC Corporation uses Mach J, an "industrially hardened" execution environment for Java bytecode that conforms to the Java Virtual Machine specification.
• Mach J has an incremental real-time garbage collector. On some other JVM's, after some period of operation, you can experience a delay in program execution while the JVM does garbage collection. Of course, these intermittent and non-deterministic pauses in program execution are inappropriate for mission critical applications. In contrast, Mach J does its garbage collection a small bit at a time, leaving predictable CPU time to your critical application code.
• Mach J was written by people who are experts in factory automation software.

If you'd like to learn more about Java language, see the Java Tutorial.