parameters : Java Glossary

parameters

parameters are always passed by value not by reference. The called method gets a copy of each primitive and a copy of the pointer to each object. The called method can therefore not change any local variables in the caller. However it can change the contents of objects (which includes strings and arrays) passed to it. Some people may argue that counts as call by reference, however a callee cannot make the callers variables point to different objects, just change the contents of objects. Objects are always accessed by reference, (literally via a reference) even when parameters are not involved. You can kludge call by reference by passing values back to your caller inside an array or by returning a freshly minted object full of values.

Difference Between Parameters and Arguments

Many people use the terms parameter and argument interchangeably, but they are different. In the definition of a method, you describe the parameter types and variable names by which they will be called inside the called method. When you invoke the method, the values you pass are called the arguments.

Parameters refer to the local names in the callee. Arguments refer to the values passed by the caller.

Learning More

Oracle’s Miscellaneous documentation on Formal Parameters

arguments
call by reference
call by value
callback
delegate
multiple return values
reference

	You can get the freshest copy of this page from:	or possibly from your local J: drive (Java virtual drive/mindprod.com website mirror)
	http://mindprod.com/jgloss/parameters.html	J:\mindprod\jgloss\parameters.html
	Please email your feedback for publication, letters to the editor, errors, omissions, typos, formatting errors, ambiguities, unclear wording, broken/redirected link reports, suggestions to improve this page or comments to Roedy Green : . If you want your message, your name or email kept confidential, not considered for public posting, please explicitly specify that. Unless you state otherwise, I will treat your message as a letter to the editor that I may or may not publish in the feedback section. After that, it will be too late to retract it. If you disagree with something I said, please quote it and cite the web page where you found it, tell me why you think it is wrong, and, if possible, provide some supporting evidence. Threatening to kill me or spouting obscenities has yet to persuade me to change my mind.
	Canadian Mind Products
	mindprod.com IP:[65.110.21.43]
view Blog	Your face IP:[38.107.179.213]
Feedback	You are visitor number 58,473.