4 Java data types
| Exam objectives covered in this chapter |
What you need to know |
| [3.1] Declare and initialize variables (including casting and promoting primitive data types) |
Declaration and initialization of primitives and object reference variables. Literal values for primitive variables. Automatic widening of data types. |
| [3.2] Identify the scope of variables |
Variables can have multiple scopes: class, instance, method, and local. Accessibility of a variable in a given scope. |
| [3.3] Use local variable type inference |
Define local variables using reserved type var. Do’s and don’ts of defining variables using var. Benefits and precautions. |
Data types and variables are the building blocks of a programming language. The Java SE 11 Programmer I exam will question you on the various primitive data types in Java, how to create and initialize variables to store primitive values and objects, and similarities and differences between them. The exam will also question you on the various scopes in which a variable can be defined, whether multiple variables with the same name can be defined in a scope and what are the implications. It also covers how to use var to define your local variables.
This chapter covers the following:
- Primitive data types in Java
- Casting and promoting primitive data types
- Reference variables
Define the scope of variables- Local Type variable inference with var
Let’s get started with Primitive data types.