concept object reference variable in category java

This is an excerpt from Manning's book OCA Java SE 8 Programmer I Certification Guide. Login to get full access to this book.

[2.2] Differentiate between object reference variables and primitive variables

2.3.2. Differentiating between object reference variables and primitive variables

Just as men and women are fundamentally different (according to John Gray, author of Men Are from Mars, Women Are from Venus), primitive variables and object reference variables differ from each other in multiple ways. The basic difference is that primitive variables store the actual values, whereas reference variables store the addresses of the objects they refer to.

Figure 2.13. Primitive variables store the actual values, whereas object reference variables store the addresses of the objects they refer to.

Other important differences between primitive variables and object reference variables are shown in figure 2.14 as a conversation between a girl and a boy. The girl represents an object reference variable and the boy represents a primitive variable. (Don’t worry if you don’t understand all of these analogies. They’ll make much more sense after you read related topics in later chapters.)