Describe the differences between program development and program execution, including the installed software required for developing and executing Java programs.

Program development is basically a step wise process to solve a particular problem. It basically refers to the coding of a program. This initial steps involves defining the problem statement, specifying the requirements and specifying what the output of the program should be. Program development also includes visually presenting what of the program for example in the form of flowchart. It also involves coding, the set of instructions, procedures, functions, sub routines that a computer should carry out to get the desired output. Also the bugs and errors are removed by debugging the program. Program execution refers to execute or run the set of instructions of a program. The program or machine code is loaded to the memory prior to execution and then executed. For example in JAVA the source code if first converted to bytecode and then in machine code in order to be executed.

Developing and Executing JAVA programs involves typing program using some editor (editing), compiling the program (converting to bytecode), loading program to memory prior to execution, verifying bytecode and executing the program.

In JAVA, Java Development Kit (JDK) is used for JAVA program development and JAVA applications development. It involves an Integrated Development Environment (IDE) which serves as a platform for writing the JAVA code.

Java Runtime Environment JRE is used to JAVA program execution and provides a platform or environment to run the JAVA applications. JRE consists of class libraries, user interface toolkit, class loader and JAVA Virtual Machine JVM.

The class loader loads the required class libraries. JVM works as an interpreter for running the JAVA program line-by-line. This interpreter executes the Byte Code.