The “javac” command is a Java application compiler. It compiles Java source code files (.java) into bytecode files (.class) that can be executed by the Java Virtual Machine (JVM). This command is essential for converting Java code into executable files. In this article, we will explore various use cases of the “javac” command with examples.

Use case 1: Compile a .java file

Code:

javac file.java

Motivation: This use case is useful when you want to compile a single Java source code file.

Explanation: The “javac” command is followed by the name of the Java source code file (file.java) that needs to be compiled.

Example Output: If the “file.java” code is error-free, the command will generate a corresponding bytecode file named “file.class” in the same directory.

Use case 2: Compile several .java files

Code:

javac file1.java file2.java file3.java

Motivation: This use case is helpful when you have multiple Java source code files that need to be compiled simultaneously.

Explanation: The “javac” command is followed by the names of the Java source code files (file1.java, file2.java, file3.java) that should be compiled.

Example Output: If all the input files are error-free, the command will generate their corresponding bytecode files in the same directory.

Use case 3: Compile all .java files in the current directory

Code:

javac *.java

Motivation: This use case is beneficial when you want to compile all the Java source code files present in the current directory.

Explanation: The “javac” command is followed by “*.java”, which is a wildcard that matches all Java source code files in the current directory.

Example Output: If all the Java files in the current directory are error-free, the command will generate their corresponding bytecode files in the same directory.

Use case 4: Compile a .java file and place the resulting class file in a specific directory

Code:

javac -d path/to/directory file.java

Motivation: This use case is useful when you want to specify a different directory to store the generated bytecode file.

Explanation: The “javac” command is followed by “-d path/to/directory”, where “path/to/directory” is the desired location where the resulting class file should be placed. The command is then followed by the name of the Java source code file (file.java) that needs to be compiled.

Example Output: If the “file.java” code is error-free, the command will generate a corresponding bytecode file named “file.class” in the specified “path/to/directory”.

Conclusion

The “javac” command is a crucial tool in Java development, allowing you to compile Java source code files into bytecode files that can be executed. By understanding the various use cases of the “javac” command and the corresponding arguments, you can efficiently compile your Java code and produce executable files.