Java Quickstart Mocktest

The correct file extension for a Java source code file is .java, distinguishing it from compiled bytecode (.class files), executable files (.exe), and Java archive files (.jar).

The main method serves as the entry point for a Java application. It is where the program begins execution when it is run.

The System.out.println() method in Java is used to print output to the console. It is commonly used for debugging purposes and to display messages or results to the user.

The class keyword is used to declare a class in Java. Classes are the fundamental building blocks of Java programs, encapsulating data and behavior.

The javac command is used to compile Java source code into bytecode. It translates human-readable Java source code into machine-readable bytecode that can be executed by the Java Virtual Machine (JVM).

Java code is typically executed on the command line using the java command followed by the name of the class containing the main method. For example, java Main would execute the main method in the Main class.

The Java Virtual Machine (JVM) is responsible for executing Java bytecode. It translates bytecode instructions into machine code that can be understood and executed by the computer's hardware.

Java's platform independence allows Java code to run on any platform with a compatible JVM (Java Virtual Machine) installed. This means that Java applications can run on Windows, macOS, Linux, and other operating systems without modification.

The javap command is used to display information about a compiled Java class, including its methods, fields, and bytecode instructions. It provides insight into the structure and behavior of Java classes.

The Java compiler (javac) translates human-readable Java source code into platform-independent bytecode, which can be executed by the Java Virtual Machine (JVM). The bytecode is stored in .class files.