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Thread: call another class

  1. #1
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    Default call another class

    may I know how to call another public class from another public class , I try to import and then call another class, it seems cant do that

  2. #2
    Super Moderator Norm's Avatar
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    Default Re: call another class

    how to call another public class from another public class
    Use a new statement to create the class and get a reference to the class. Then use that reference to call method:
      TheClass theClass = new TheClass();   // create instance and set reference
       theClass.theMethod();    // call a method in the other class

    Post any code that you are having problems with. Also copy and paste any error messages here.

    Note: You do not call classes, you call methods in a class.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: call another class

    Quote Originally Posted by Norm View Post
    Use a new statement to create the class and get a reference to the class. Then use that reference to call method:
      TheClass theClass = new TheClass();   // create instance and set reference
       theClass.theMethod();    // call a method in the other class

    Post any code that you are having problems with. Also copy and paste any error messages here.
    @component
    public class anotherClass implements ownClass {

    @Autowired
    private MqMsgModel mqMsgConvertor;

    @Override
    public mqMsg mqTemplate (MqMsg mqMsg) {

    try {
    mqMsg.getMsgHeader().setTime(new Date());
    catch( Exception e) {
    e.printStackTrace()
    }
    }

    }

    }


    what is @component, @Autowired, @Override from above coding? what is function ? and what type of java programming?

    i want to call above class "mqTemplate " by passing parameter "mqMsg" from another public class, how can i do that?

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: call another class

    i want to call above class "mqTemplate "
    Are you referring to calling the class's constructor when creating an instance of the class?

    Did you get any error messages? Please copy the full text and paste it here.

    what is @component, @Autowired, @Override
    I do not recognize the first two annotations.
    @Override is used when extending a class or implementing an interface and you want to ask the compiler to check if your method override is correct.

    Read the tutorial about annotations: https://docs.oracle.com/javase/tutor...ons/index.html

    Please edit your post and wrap your code with code tags:

    [code]
    **YOUR CODE GOES HERE**
    [/code]

    to get highlighting and preserve formatting.
    If you don't understand my answer, don't ignore it, ask a question.

  5. #5
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    Default Re: call another class

    Quote Originally Posted by Norm View Post
    Are you referring to calling the class's constructor when creating an instance of the class?

    Did you get any error messages? Please copy the full text and paste it here.


    I do not recognize the first two annotations.
    @Override is used when extending a class or implementing an interface and you want to ask the compiler to check if your method override is correct.

    Read the tutorial about annotations: https://docs.oracle.com/javase/tutor...ons/index.html

    Please edit your post and wrap your code with code tags:

    [code]
    @component
    public class anotherClass implements ownClass {

    @Autowired
    private MqMsgModel mqMsgConvertor;

    @Override
    public mqMsg mqTemplate (MqMsg mqMsg) {

    try {
    mqMsg.getMsgHeader().setTime(new Date());
    catch( Exception e) {
    e.printStackTrace()
    }
    }

    }

    }
    [/code]

    to get highlighting and preserve formatting.
    if i want to call above class from another public class, i just create instance and call its method.
    here is my coding.
     
     anotherClass tryClass= new anotherClass ();   // create instance and set reference
       mqMsg testMsg=tryClass.mqTemplate (mqMsg);    // call a method in the other class

    [code in another class] is it correct?
    Last edited by Norm; June 16th, 2020 at 10:55 AM. Reason: Fixed code tags

  6. #6
    Super Moderator Norm's Avatar
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    Default Re: call another class

    is it correct?
    It could be. Did you try it to see what happens?

    Please wrap all posted code in code tags.

    There is one confusing bit in the code
    mqMsg
    is shown as both the name of a class and the name of a variable.
    If you don't understand my answer, don't ignore it, ask a question.

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