The difference between compiling and running in java

Compilation in Java converts source code into bytecode for syntax and logic checking and to increase execution speed. Runs on the JVM to execute bytecode, including class loading, instance creation, method execution, and error handling. The main differences include: time (compilation is executed first, running is performed dynamically), output (compilation into bytecode, running as the result), error checking (compiling to detect syntax, running to detect runtime errors), dependencies (compilation depends on the compiler, Runtime dependent on JVM) and flexibility (bytecode is executable across JVMs).

The difference between compilation and running in Java

In Java, compilation and running are two completely different things Process is crucial to understanding how Java works.

Compilation

Compilation is a process of converting Java source code (.java file) into bytecode (.class file). Bytecode is a machine-readable set of instructions that can be executed on a Java Virtual Machine (JVM). Compilation is typically performed by the Java compiler (javac).

The main purpose of compilation is:

• Check for syntax errors and logical errors in the code.
• Convert Java code to faster bytecode format.
• Ensure that the bytecode is compatible with the standards specified by the JVM.

Running

Running is the process of executing bytecode instructions on the JVM. The JVM is responsible for interpreting the bytecode and executing the behavior it represents. Runtime is typically performed by the Java Runtime Environment (JRE).

The main purpose of running is:

• Dynamic loading of classes.
• Create class instance.
• Execution methods and constructors.
• Handling exceptions and errors.

Differences

The key differences between compiling and running are as follows:

• Time: Compile Usually executed once before the program is run, while execution occurs dynamically while the program is running.
• Output: Compilation produces bytecode files, and running produces actual behavior and results.
• Error checking: Compilation is mainly used to detect syntax errors, while running will detect runtime errors, such as null pointer exceptions.
• Dependencies: Compilation depends on the Java compiler, and running depends on the Java virtual machine.
• Flexibility: Bytecode can run on different JVMs, while Java code can only be compiled on a specific compiler version.

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