What's the difference between primitive and reference types?

java types reference primitive
WestJackson picture WestJackson · Jan 9, 2012 · Viewed 172.8k times · Source

This is a past exam question and I was wondering what a primitive type and reference type are first off? With an array I know the a reference type is where the array is composed of objects or variables, but a primitive type is where you would create the array with just int or strings. (right?)

How do you think you would answer the question on the test and be given good credit? Without really referring directly to an primitive ARRAY type... Is there a way to do it without that? Or do you think it would be fine to just explain it with the array.

Answer

BERGUIGA Mohamed Amine picture BERGUIGA Mohamed Amine · Aug 17, 2015

From book OCA JAVA SE 7

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. Let’s assume that a class Person is already defined. If you create an int variable a, and an object reference variable person, they will store their values in memory as shown in figure 2.13.

int a = 77;
Person person = new Person();

enter image description here

Related questions

java : convert float to String and String to float

How could I convert from float to string or string to float? In my case I need to make the assertion between 2 values string (value that I have got from table) and float value that I have calculated. String valueFromTable = "25"; …

Read More
Converting stream of int's to char's in java

This has probably been answered else where but how do you get the character value of an int value? Specifically I'm reading a from a tcp stream and the readers .read() method returns an int. How do I get a …

Read More
How do you know a variable type in java?

Let's say I declare a variable: String a = "test"; And I want to know what type it is, i.e., the output should be java.lang.String How do I do this?

Read More