Introduction to Annotations2:16 with Chris Ramacciotti
During this first video, we get a high-level look at what Java annotations look like in code, and at what they can do for us.
The Java compiler you use - likely javac or Eclipse Compiler for Java (ECJ) if you're using Eclipse - is what translates your source code in Java bytecode. As a developer, you code the ".java" files, and from these the compiler creates ".class" files (bytecode). This bytecode is what is actually loaded into the Java Virtual Machine (JVM) when you run your Java application.
What makes Java applications so portable is that in general, Java bytecode can run on any device that contains a valid implementation of a JVM. This implementation could be a JVM written for a Linux machine, Mac, PC, or another platform. The JVM is what will compile bytecode to the machine code that is understood natively by the machine on which it is running. The JVMs for each platform had to be created separately, since how a JVM interacts with Windows is different than how it must interact with OSX, for example.
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