What is the difference between local and instance variables in Java?

by

The main differences that I see are in their:

Scope: Local variables are visible only in the method or block they are declared whereas instance variables can been seen by all methods in the class.

Place where they are declared: Local variables are declared inside a method or a block whereas instance variables inside a class, but outside a method.

Existence time: Local variables are created when a method is called and destroyed when the method exits whereas instance variables are created using new and destroyed by the garbage collector when there aren’t any reference to them.

Access: You can’t access local variables, whereas instance variables can be accessed if they are declared as public.

Where they are declared: Local variables are declared in a method or a block before they are called, whereas instance variables can be declared anywhere in the class level (even after their use).

Instance variables always have value, even if they are not assigned by the code (then they will have for example null, 0, 0.0, and false). For local variables, there must be an assigned value by the code. Otherwise the compiler generates an error.

More Related Contents:

  1. to output all elements of square matrix in a spiral
  2. when to override hashcode and equals method in java [duplicate]
  3. Alarm Manager Example
  4. Java: splitting a comma-separated string but ignoring commas in quotes
  5. How to read XML using XPath in Java
  6. Maven dependencies are failing with a 501 error
  7. Any reason to prefer getClass() over instanceof when generating .equals()?
  8. Manifest merger failed : Attribute application@appComponentFactory cant solve this
  9. Servlet vs Filter
  10. How to set thousands separator in Java?
  11. Spring boot @ResponseBody doesn’t serialize entity id
  12. is there a ‘block until condition becomes true’ function in java?
  13. What are the pros and cons of performing calculations in sql vs. in your application
  14. How to resize text in java
  15. Annotations from javax.validation.constraints not working
  16. JPA Criteria API – How to add JOIN clause (as general sentence as possible)
  17. IntelliJ and JSP/JSTL cannot resolve taglib for JSTL in tomcat7 [duplicate]
  18. Java class name containing dollar sign fails to compile if an inner class is present
  19. Write HTML file using Java
  20. Java rounding up to an int using Math.ceil
  21. Any good Spring threading with a TaskExecutor examples? [closed]
  22. IntelliJ Compilation Error zip END header not found
  23. Firebase can’t save retrieved data to ArrayList
  24. Merging Two JSON Documents Using Jackson
  25. How to set timezone to UTC in Apache Spark?
  26. Autowiring in Spring bean (@Component) created with new keyword
  27. Powershell: Capturing standard out and error with Process object
  28. Java enum valueOf() with multiple values?
  29. How to read UTF8 encoded file using RandomAccessFile?
  30. Why doesn’t my string comparison work?

Leave a Comment