J2EEOnline J2EE 

Java Technology  «Prev  Next»
Lesson 7

Java SDK Conclusion

This module introduced you to Java, the Java 2 Software Development Kit (SDK), and some of the most important tools the Java 2 SDK provides. You began the module by learning about the benefits of Java as a software technology.
You then moved on to downloading, installing, and configuring the Java 2 SDK. From there, you learned how to use the Java compiler to compile Java programs into bytecode executables.
You also learned how to use the AppletViewer to test applets without relying on a Web browser. You then concluded the module by running a command-line Java application using the Java interpreter.

Glossary Terms
This module discussed how the following terms relate to Java:
  1. Bytecode: Bytecode is the executable form of Java code, which is capable of being executed in the Java runtime system.
  2. AppletViewer: AppletViewer is a utility included with the Java Development Kit that allows you to test applets without using a Web browser.
  3. Java interpreter:The Java interpreter is a program responsible for translating Java bytecode into native code that can execute on a given platform .

The Java Virtual Machine needs to verify for itself that the desired constraints are satisfied by the class files it attempts to incorporate. A Java Virtual Machine implementation verifies that each class file satisfies the necessary constraints at linking time. Linking-time verification enhances the performance of the interpreter. Expensive checks that would otherwise have to be performed to verify constraints at run time for each interpreted instruction can be eliminated. The Java Virtual Machine can assume that these checks have already been performed. For example, the Java Virtual Machine will already know the following:
  1. There are no operand stack overflows or underflows.
  2. All local variable uses and stores are valid.
  3. The arguments to all the Java Virtual Machine instructions are of valid types.
Java Fundamentals - Quiz
Click the Quiz link below to test what you have learned in this module.
Java Fundamentals - Quiz