Executing native shell commands from Java Program - Java.lang.Runtime.exec() Method

Executing native shell commands from Java Program - Java.lang.Runtime.exec() Method

Java.lang.Runtime.exec can be used to execute native shell commands from Java Program. Running native shell commands from Java is not recommended because by doing so you will lose platform independence which is one reason why we use JAVA.

Suppose you want to find files/directories in "C:\Users\josemel\", this can be done from terminal in two ways
1. Navigate to required directory and run "dir" OR
2. Run "dir " from anywhere

The above can be done from Java using exec() function as shown below.

JAVA DOC

Java.lang.Runtime.exec(String[] cmdarray, String[] envp) Method - Executes the specified command and arguments in a separate process with the specified environment.

Parameters:

• cmdarray - array containing the command to call and its arguments.
• envp - array of strings, each element of which has environment variable settings in the format name=value, or null if the subprocess should inherit the environment of the current process.

Returns:
A new Process object for managing the subprocess

Throws:

• SecurityException - If a security manager exists and its checkExec method doesn't allow creation of the subprocess
• IOException - If an I/O error occurs
• NullPointerException - If cmdarray is null, or one of the elements of cmdarray is null, or one of the elements of envp is null
• IndexOutOfBoundsException - If cmdarray is an empty array (has length 0)