When you run your Java program (stored in .java files) in Eclipse, the following happens. The java compiler (named javac) runs and translates your program from Java Programming language into Java Virtual Machine Language (JVML) also called byte code and stores it into .class files. Then the Java interpreter (named java) runs and executes instruction by instruction the byte code stored in .class files. First, it translates a one byte code instruction into its equivalent machine language instruction/s and then executes the machine language instruction/s. It repeats this process for the next byte code instruction and so on.

If any errors occur while the compiler is translating (compiling) the program from .java files into .class files, those errors are called compiler or syntax errors. If any errors occur while the interpreter is executing the byte code instructions stored in .class files, those errors are considered runtime errors. What are the runtime errors called in Java terminology?