https://medium.com/@dammnn/how-data-types-and-operators-work-in-java-5eedb9f7fcda

google.com/imagesData types and operators are a large subject. We will begin here with an examination of Java’s foundational data types and its most commonly used operator. We will also take a closer look at variables and examine the expression.

Data types are especially important in Java because it is a strongly typed language. This means that all operations are type checked by the compiler for type compatibility. Illegal operations will not be compiled. Thus, strong type checking helps prevent error and enhance reliability. To enable strong type checking, all variables, expressions, and values have a type. There is no concept of a type-less variable. Furthermore, the type of value determines what operations are allowed on it. An operation allowed on one type might not be allowed on another.