In Java, you use variables for storing and retrieving data for your program. Arithmetic operators let you specify how the numerical values within variables should be evaluated or combined. This course covers the uses of variables and defining the syntax for a variable. It introduces Java programming language primitive data types, and declaring, initializing, and using variables and constants, as well as modifying variable values by using operators. it also demonstrates using promotion and type casting. In addition, this course explores declaring, instantiating, and initializing objects, working with object references, and using the String class, StringBuilder class, and the Java API documentation.