Java Keywords

ND079 C1 L1 A02 Java Keywords Video

If we want to build an application in Java, we first need to know the basic vocabulary of the language. This vocabulary is made up of what we call keywords.

Keywords are simply words that have a predefined meaning in the Java language.

Java has 51 keywords, as shown in the table below.

		Java Keywords
abstract	continue	for	new	super
assert	default	goto	null	switch
boolean	do	if	package	synchronized
break	double	implements	private	this
byte	else	import	protected	throw
case	enum	instanceof	public	throws
catch	extends	int	return	transient
char	final	interface	short	try
class	finally	long	static	void
const	float	native	strictfp	volatile
while

You don't need to memorize these—you will get familiar with many of them in this course, and the rest you can always look up if you need them. But the key thing to remember is that these words already have a meaning in Java, so they are reserved. That means you cannot use them when you are naming your own variables, methods or classes.

SOLUTION:

They are reserved words in the Java Language
They cannot be used as identifiers (e.g., when naming variables, classes, or methods)
There are 51 keywords in Java