This week's book giveaway is in the Open Source forum.
We're giving away four copies of Programmers Guide to Apache Thrift and have Randy Abernethy on-line!
See this thread for details.
Win a copy of Programmers Guide to Apache Thrift this week in the Open Source forum!
    Bookmark Topic Watch Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Devaka Cooray
  • Knute Snortum
  • Paul Clapham
  • Tim Cooke
Sheriffs:
  • Liutauras Vilda
  • Jeanne Boyarsky
  • Bear Bibeault
Saloon Keepers:
  • Tim Moores
  • Stephan van Hulst
  • Ron McLeod
  • Piet Souris
  • Frits Walraven
Bartenders:
  • Ganesh Patekar
  • Tim Holloway
  • salvin francis
  • Likes 1
  • Mark post as helpful
  • send pies
  • Report post to moderator
Java always makes a copy of the argument and passes the copy. The called method has a local copy of the data. If the method changes the data it changes the copy, so the original value is not changed.

When we pass a primitive like int this make perfect sense. The method gets its own int variable, a copy of the original.

When we pass an object we have to think very precisely. The value that is copied and sent along is a reference or pointer to the object. The method gets its own copy of the pointer, but it doesn't get its own copy of the object. If the method changes its copy of the pointer to point to a different object the original pointer is not affected. If the method changes some of the attributes of the object, it changes the original object.

In short: In Java, object references are passed by value and primitive types are passed by value.

(posted by Stan James in this thread)

Other Resources:

  • http://www.javaranch.com/campfire/StoryPassBy.jsp
  • relevant section of the Java Language Specification

  •  
    it's a teeny, tiny, wafer thin ad:
    ScroogeXHTML - small and flexible RTF to HTML converter library
    https://coderanch.com/t/710903/ScroogeXHTML-RTF-HTML-XHTML-converter
      Bookmark Topic Watch Topic
    • New Topic
    Boost this thread!