Final answer:
The Java compiler takes .java files as input and outputs .class files containing bytecode that can be executed by the Java Virtual Machine (JVM).
Step-by-step explanation:
The input of a Java compiler is Java source code, which is written in .java files. This source code is composed of the syntax and instructions that adhere to the Java programming language. Upon compiling, these .java files are processed into bytecode, which is a set of instructions that the Java Virtual Machine (JVM) understands and can execute.
The output of the Java compiler is a .class file containing this bytecode. Unlike the human-readable source code, bytecode is a lower-level, binary representation of the program that can be directly interpreted by the JVM. Each .class file corresponds to a single Java class from the source code.
In summary, for a Java compiler the input is Java source code (.java files), and the output is Java bytecode (.class files), which is then run on the JVM.
For example, if a programmer writes a Java program to calculate the sum of two numbers, they would input the source code, including the necessary instructions and variables. The compiler would then transform this source code into bytecode, which can be run on any system with a JVM.