4.3) Java Key words

Index

Objective 4, identify keywords

Identify all Java programming language keywords. Note: There will not be any questions regarding esoteric distinctions between keywords and manifest constants.

Note on this objective: You may like to approach this objective on the basis of learning the less frequently used key words and ensuring you do not carry over any "false friends" from other languages you may know, particularly C/C++. The exam places significant emphasis on recognising keywords. The second part of this objective mentioning esoteric distinctions was added with the objectives for the JDK 1.4 version of the exam. It seems to have grown out of the number of people worrying if true/false and null were keywords. I think you can take it from this comment that you will not be questioned on true/false and null.

Java Keywords

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

You will come to recognise most of the Java keywords through using the language, but there are rarely used exceptions, and reserved words that might come up in the exam.

Examples of the more rarely used words (certainly for a beginner anyway) are

volatile
transiernt
native
strictfp

The words with asterisks are reserved and not currently used. Note that all of the keywords are in lowercase, thus for is a keyword but FOR is not.

Questions

Question 1)

Which of the following are Java key words?

1) double
2) Switch
3) then
4) instanceof

Question 2

Which of the following are not Java keywords?

1)volatile
2)sizeOf
3)goto
4)try

Answers

Answer 1)

1) double
4) instanceof

Note the upper case S on switch means it is not a keyword and the word then is part of Visual Basic but not Java

Answer 2)

2) sizeOf

This is a keyword in C/C++ for determining the size of a primitive for a particular platform. Because primitives have the same size on all platforms in Java this keyword is not needed.