How to define variables in Java.

In Java, variables can be defined by using keywords like “int”, “float”, “double”, “boolean”, and assigned values using the equal sign “=”. Here are some examples:

1. Create an integer variable named x and assign it the value of 5.
2. Define a float variable y and assign the value of 3.14.
3. Define a boolean variable named isTrue and initialize it with the value true.
4. Declare a string variable named name and assign the value “John” to it:
   String name = “John”;

Please note that variables must be named according to Java naming conventions, with the first letter not being a number and including letters, numbers, and underscores.