What does a Java Virtual Machine (VM) do?

A Java Virtual Machine (VM) serves a crucial role in the execution of Java programs by converting compiled Java bytecode into machine code that can be executed by the host operating system. When a Java program is written, it undergoes a compilation process that translates the high-level Java code into bytecode, which is an intermediate representation. The Java Virtual Machine then reads this bytecode and translates it into machine code suitable for the specific hardware, allowing the program to run on any device that has the Java VM installed. This capability is what makes Java a "write once, run anywhere" language, as the bytecode is platform-independent, and the Java VM handles the specifics of the execution on different systems.

This function of converting source code into machine code is fundamental to how Java operates and plays a significant role in the portability and versatility of Java applications. While the other options touch on aspects related to programming and application management, they do not accurately describe the primary function of the Java VM.