Computer Science Terms

Any time you learn a new subject, computer science included, you’ll find new terms. To help out we’re building this glossary of computer science terms.

This particular list is geared mainly towards Java programming, although many of the terms are relevant whatever language you’re learning.


Symbol used to check if two values are not equivalent.
1 != 2
Logical and. Used to combine two boolean conditions where both conditions must be true for the combined statement to be true.
true && true == true
true && false == false
false && true == false
false && false == false
Two equals signs are used to test equality.
int x = 2;
int y = 3;
if (x == y)
   System.out.println("They're equal!");
Logical or. Used to combine two boolean conditionals where the combined statement is true if either side of the or is true.
true || true == true
true || false == true
false || true == true
false || false == false


abstract class
A class that cannot be instantiated and may contain abstract methods
abstract method
A method with a name, parameter types and return type; but without implementation. Typically used within an abstract class when the implementation is not known for a specific method.
Bit of data specified in a method call. Typically a literal value or a variable.
Exception thrown when an impossible math condition is used. Most common example is when you try to divide by zero.
A collection of data items. Depending on the language they may all have to be the same type. In some languages arrays are a fixed size.


A group of statements. In Java, and many other languages,  blocks are surrounded by { and } symbols.
Primitive data type with only two possible values, true or false.
Keyword used to exit a loop and start execution at the next line following the loop. Also used in switch case statements.


Changing one data type to another.


An event that disrupts the normal flow of a program


A primitive data type that can hold a whole number in the range \( -2^{31} ... 2^{31} - 1\)


Java subset
A subset of the Java language that the College Board expects you to know for the Computer Science AP-A exam. You can find a copy here.


Exception thrown when trying to access a property or method of a null object.