What is that crazy Java ^ character?

Operators in Java – Basic Language Symbology for Beginners

Or… What does that crazy ‘^’ symbol mean anyway?

Java has (as of this writing in Java 1.7) 37 tokens that are designated as operators. (See the Java Language Specification http://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.12”>here.

Non-assignment tokens are always evaluated left to right, with a set of precedence rules applied. Assignment tokens evaluate right to left. Order of precedence tells us that a complex statement with lots of operators will be guaranteed to be evaluated in a reliable order. I won’t cover the specifics of order in this entry… they’re very nicely charted in the Oracle Java Tutorial link at the end of this post.

An oft-asked question I receive from “future Java gurus” (beginners J) is, “What is that char and what does it mean?” Or “what is the difference between ‘&’ and ‘&&’?”

I know computer science training helps a lot, but if you’re like me, you might have bootstrapped yourself into software engineering without an official BS/CS degree completion. 

I thought I would encapsulate a few of the most common things that beginners tend to ask, and put them in human-readable form. This isn’t intended to be a be-all and define-all, just a quick post to get your head wrapped around a few less-commonly-used operators.

Remember: if your statement gets long and hairy, you can always break it down into smaller parts, or you can use parentheses to “force” precedence.

& The bitwise AND operator (applies to integral/primitive types) also works with booleans

int resultingInt = 12 & 15;

//resultingInt is now assigned with the integer 12

//it helps to understand the binary representations of the operands to see how this works

//homework: why 12?

| The bitwise inclusive OR operator (applies to integral/primitive types) also works with booleans

int resultingInt = 12 | 15;

//resultingInt is now assigned with the integer 15

//it helps to understand the binary representations of the operands to see how this works

//homework: why 15

^ the bitwise exclusive OR operator (applies to integral/primitive types) also works with booleans

int resultingInt = 12 ^ 15;

//resultingInt is now assigned with the integer 3

//it helps to understand the binary representations of the operands to see how this works

//homework: why 3?

&& the logical AND operator

boolean isTrue = boolean1 && boolean2;

//in English: “if boolean1 is true AND boolean2 is true, assign true to isTrue,

//else, assign false to isTrue”

//This operator is”fail fast.” If the first operand is false, the second isn’t evaluated.

|| the logical OR operator

boolean isTrue = boolean1 || boolean2;

//in English: “if boolean1 is true OR boolean2 is true, assign true to isTrue,

//else, assign false to isTrue”

variable = ? : ; The ternary operator

int firstYear = 0;

int lastYear = 12;

boolean isLastYearLater = lastYear < firstYear ? false : true;

//in English: “if last year is less than firstYear,

//assign false to isLastYearLater, else assign true to isLastYearLater”

Want to know more? Ask the source! The Java Tutorials have a nice concise up-to-date page here: http://docs.oracle.com/javase/tutorial/java/nutsandbolts/operators.html”> http://docs.oracle.com/javase/tutorial/java/nutsandbolts/operators.html

Want to see a glimpse of how the bitwise operators work? http://www.leepoint.net/notes-java/data/expressions/bitops.html">This is a good starting point.