Solved

True & flase Statements

Posted on 2002-04-17
1
235 Views
Last Modified: 2010-03-31
hi..i need to know if the following sentences are true or false..and why? simple explanation plz

1) subclass variables should be defind as private to hide them from other subclasses. (        )
2) main method can't directly access any non static method and varibales,but using the instance of the class it can.!!!!!!


my comments or concerns..for the following :
1) i guess it should be true.. cuz of the encapsulation.. am i right..or it's not forced to be private .. only it's a better way to hide variables.. ?!?!!/ i'm not sure.just giving what i know..and waiting for ur answer

2) but why other static methods can't use instance of the class?!?!!?

hope i've made myself clear enough to get ur answers..
i'll be waiting..
0
Comment
Question by:ms_lost
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 86

Accepted Solution

by:
CEHJ earned 10 total points
ID: 6949262
1. True. As you say 'cuz of the encapsulation'. This is true generally of any class, not just subclasses. This prevents client classes from directly accessing the fields directly. Using accessor methods (get/set) provides a useful layer of indirection, such that the method may do things other than simple assignments (this.someProp = someProp).
2. True. 'but why other static methods can't use instance of the class?!?!!?' They can:

zclass StaticAccess {

  /**
   * Note that this variable must be declared 'static' to be accessible from
   * accessInstance() or any other static method
  */
  static StaticAccess instance;

  public static void accessInstance() {
    instance.printMessage();
  }
     
  public void printMessage(){
    System.out.println("In instance method");
  }

  public static void main(String[] args) {
    // Comment the next line out. What will the result be?
    instance = new StaticAccess();
    StaticAccess.accessInstance();
  }
}
0

Featured Post

On Demand Webinar: Networking for the Cloud Era

Did you know SD-WANs can improve network connectivity? Check out this webinar to learn how an SD-WAN simplified, one-click tool can help you migrate and manage data in the cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Java had always been an easily readable and understandable language.  Some relatively recent changes in the language seem to be changing this pretty fast, and anyone that had not seen any Java code for the last 5 years will possibly have issues unde…
Java Flight Recorder and Java Mission Control together create a complete tool chain to continuously collect low level and detailed runtime information enabling after-the-fact incident analysis. Java Flight Recorder is a profiling and event collectio…
Viewers learn about the third conditional statement “else if” and use it in an example program. Then additional information about conditional statements is provided, covering the topic thoroughly. Viewers learn about the third conditional statement …
Viewers will learn about the different types of variables in Java and how to declare them. Decide the type of variable desired: Put the keyword corresponding to the type of variable in front of the variable name: Use the equal sign to assign a v…

695 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question