How to prevent changing the value of variable? The Next CEO of Stack OverflowIs Java “pass-by-reference” or “pass-by-value”?How do I efficiently iterate over each entry in a Java Map?Sort a Map<Key, Value> by valuesHow do I call one constructor from another in Java?How do I read / convert an InputStream into a String in Java?How do I generate random integers within a specific range in Java?How to get an enum value from a string value in Java?How do I determine whether an array contains a particular value in Java?How do I convert a String to an int in Java?How do I fix android.os.NetworkOnMainThreadException?

How do we know the LHC results are robust?

Is "for causing autism in X" grammatical?

How to start emacs in "nothing" mode (`fundamental-mode`)

Why does the UK parliament need a vote on the political declaration?

What is the purpose of the Evocation wizard's Potent Cantrip feature?

What is the result of assigning to std::vector<T>::begin()?

Why am I allowed to create multiple unique pointers from a single object?

Contours of a clandestine nature

What flight has the highest ratio of time difference to flight time?

Why does standard notation not preserve intervals (visually)

What happened in Rome, when the western empire "fell"?

What is "(CFMCC)" on an ILS approach chart?

How do I reset passwords on multiple websites easily?

I believe this to be a fraud - hired, then asked to cash check and send cash as Bitcoin

In the bitcoin scripting language, how can I access other outputs of the transaction? Or how else can I limit how the coins may be spent?

sp_blitzCache results Memory grants

MessageLevel in QGIS3

Help understanding this unsettling image of Titan, Epimetheus, and Saturn's rings?

Why do airplanes bank sharply to the right after air-to-air refueling?

Several mode to write the symbol of a vector

How do I go from 300 unfinished/half written blog posts, to published posts?

Elegant way to replace substring in a regex with optional groups in Python?

What happens if you roll doubles 3 times then land on "Go to jail?"

Is it my responsibility to learn a new technology in my own time my employer wants to implement?



How to prevent changing the value of variable?



The Next CEO of Stack OverflowIs Java “pass-by-reference” or “pass-by-value”?How do I efficiently iterate over each entry in a Java Map?Sort a Map<Key, Value> by valuesHow do I call one constructor from another in Java?How do I read / convert an InputStream into a String in Java?How do I generate random integers within a specific range in Java?How to get an enum value from a string value in Java?How do I determine whether an array contains a particular value in Java?How do I convert a String to an int in Java?How do I fix android.os.NetworkOnMainThreadException?










7















I am a beginner in java. When developing a program, I created an object with a constructor with variables as arguments. But when I change the value of the variable after creating the object, my object has the second value instead of the first one. I don't want my object to change the value. What do I do?



public class Person 

public Person(int[] arrayTest)
this.arrayTest = arrayTest;

public int[] getArray()
return this.arrayTest;

public boolean canHaveAsArray(int[] arrayTest)
return true;

private int[] arrayTest = new int[2];

public static void main(String[] args)
int[] array = new int[] 5, 10;
Person obj1 = new Person(array);
array[0] = 20;
System.out.println(Arrays.toString(obj1.getArray()));




My output should be [5, 10], but instead, I am getting [20,10]. I need to get [5,10] even when I change an element of the array as shown above. What should I do?










share|improve this question


























    7















    I am a beginner in java. When developing a program, I created an object with a constructor with variables as arguments. But when I change the value of the variable after creating the object, my object has the second value instead of the first one. I don't want my object to change the value. What do I do?



    public class Person 

    public Person(int[] arrayTest)
    this.arrayTest = arrayTest;

    public int[] getArray()
    return this.arrayTest;

    public boolean canHaveAsArray(int[] arrayTest)
    return true;

    private int[] arrayTest = new int[2];

    public static void main(String[] args)
    int[] array = new int[] 5, 10;
    Person obj1 = new Person(array);
    array[0] = 20;
    System.out.println(Arrays.toString(obj1.getArray()));




    My output should be [5, 10], but instead, I am getting [20,10]. I need to get [5,10] even when I change an element of the array as shown above. What should I do?










    share|improve this question
























      7












      7








      7








      I am a beginner in java. When developing a program, I created an object with a constructor with variables as arguments. But when I change the value of the variable after creating the object, my object has the second value instead of the first one. I don't want my object to change the value. What do I do?



      public class Person 

      public Person(int[] arrayTest)
      this.arrayTest = arrayTest;

      public int[] getArray()
      return this.arrayTest;

      public boolean canHaveAsArray(int[] arrayTest)
      return true;

      private int[] arrayTest = new int[2];

      public static void main(String[] args)
      int[] array = new int[] 5, 10;
      Person obj1 = new Person(array);
      array[0] = 20;
      System.out.println(Arrays.toString(obj1.getArray()));




      My output should be [5, 10], but instead, I am getting [20,10]. I need to get [5,10] even when I change an element of the array as shown above. What should I do?










      share|improve this question














      I am a beginner in java. When developing a program, I created an object with a constructor with variables as arguments. But when I change the value of the variable after creating the object, my object has the second value instead of the first one. I don't want my object to change the value. What do I do?



      public class Person 

      public Person(int[] arrayTest)
      this.arrayTest = arrayTest;

      public int[] getArray()
      return this.arrayTest;

      public boolean canHaveAsArray(int[] arrayTest)
      return true;

      private int[] arrayTest = new int[2];

      public static void main(String[] args)
      int[] array = new int[] 5, 10;
      Person obj1 = new Person(array);
      array[0] = 20;
      System.out.println(Arrays.toString(obj1.getArray()));




      My output should be [5, 10], but instead, I am getting [20,10]. I need to get [5,10] even when I change an element of the array as shown above. What should I do?







      java






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked 1 hour ago









      OpheliaOphelia

      362




      362






















          2 Answers
          2






          active

          oldest

          votes


















          5














          Array is passed by reference in Java. If you pass the original array to the constructor of Person, you are just passing the reference to the original array and the changes in original array will reflect in Person instance.



          So if you don't want to change the value of array in Person so don't pass the original array, instead just send a copy of original array like below:



          Person obj1 = new Person(java.util.Arrays.copyOf(array, array.length));


          You can also modify the code in Person constructor to achieve the same results:



          public Person(int[] arrayTest) 
          this.arrayTest = java.util.Arrays.copyOf(arrayTest, arrayTest.length);






          share|improve this answer
































            3














            There is no such thing as immutable (unchangeable) array in Java. The Java language does not support this, and neither does the JVM. You can't solve this at the language level.



            In general, the only way to prevent changes to an array is to not share the reference to the array with other code that might change it.



            In your example, you have what is known as a leaky abstraction. You are passing an array to your Person class, and the caller is keeping a reference to that array so that it can change it. To solve this, you can:



            • copy the array, and pass a reference to the copy, or

            • have the constructor (or a setter for the array attribute) make the copy.

            (See answer https://stackoverflow.com/a/55428214/139985 for example code.)



            The second alternative is preferable from an OO perspective. The Person class should be responsible for preserving its own internal state from interference ... if that is your design requirement. It should not rely on the caller to do this. (Even if the caller is technically part of the same class as is the case here.)






            share|improve this answer

























              Your Answer






              StackExchange.ifUsing("editor", function ()
              StackExchange.using("externalEditor", function ()
              StackExchange.using("snippets", function ()
              StackExchange.snippets.init();
              );
              );
              , "code-snippets");

              StackExchange.ready(function()
              var channelOptions =
              tags: "".split(" "),
              id: "1"
              ;
              initTagRenderer("".split(" "), "".split(" "), channelOptions);

              StackExchange.using("externalEditor", function()
              // Have to fire editor after snippets, if snippets enabled
              if (StackExchange.settings.snippets.snippetsEnabled)
              StackExchange.using("snippets", function()
              createEditor();
              );

              else
              createEditor();

              );

              function createEditor()
              StackExchange.prepareEditor(
              heartbeatType: 'answer',
              autoActivateHeartbeat: false,
              convertImagesToLinks: true,
              noModals: true,
              showLowRepImageUploadWarning: true,
              reputationToPostImages: 10,
              bindNavPrevention: true,
              postfix: "",
              imageUploader:
              brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
              contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
              allowUrls: true
              ,
              onDemand: true,
              discardSelector: ".discard-answer"
              ,immediatelyShowMarkdownHelp:true
              );



              );













              draft saved

              draft discarded


















              StackExchange.ready(
              function ()
              StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55428172%2fhow-to-prevent-changing-the-value-of-variable%23new-answer', 'question_page');

              );

              Post as a guest















              Required, but never shown

























              2 Answers
              2






              active

              oldest

              votes








              2 Answers
              2






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes









              5














              Array is passed by reference in Java. If you pass the original array to the constructor of Person, you are just passing the reference to the original array and the changes in original array will reflect in Person instance.



              So if you don't want to change the value of array in Person so don't pass the original array, instead just send a copy of original array like below:



              Person obj1 = new Person(java.util.Arrays.copyOf(array, array.length));


              You can also modify the code in Person constructor to achieve the same results:



              public Person(int[] arrayTest) 
              this.arrayTest = java.util.Arrays.copyOf(arrayTest, arrayTest.length);






              share|improve this answer





























                5














                Array is passed by reference in Java. If you pass the original array to the constructor of Person, you are just passing the reference to the original array and the changes in original array will reflect in Person instance.



                So if you don't want to change the value of array in Person so don't pass the original array, instead just send a copy of original array like below:



                Person obj1 = new Person(java.util.Arrays.copyOf(array, array.length));


                You can also modify the code in Person constructor to achieve the same results:



                public Person(int[] arrayTest) 
                this.arrayTest = java.util.Arrays.copyOf(arrayTest, arrayTest.length);






                share|improve this answer



























                  5












                  5








                  5







                  Array is passed by reference in Java. If you pass the original array to the constructor of Person, you are just passing the reference to the original array and the changes in original array will reflect in Person instance.



                  So if you don't want to change the value of array in Person so don't pass the original array, instead just send a copy of original array like below:



                  Person obj1 = new Person(java.util.Arrays.copyOf(array, array.length));


                  You can also modify the code in Person constructor to achieve the same results:



                  public Person(int[] arrayTest) 
                  this.arrayTest = java.util.Arrays.copyOf(arrayTest, arrayTest.length);






                  share|improve this answer















                  Array is passed by reference in Java. If you pass the original array to the constructor of Person, you are just passing the reference to the original array and the changes in original array will reflect in Person instance.



                  So if you don't want to change the value of array in Person so don't pass the original array, instead just send a copy of original array like below:



                  Person obj1 = new Person(java.util.Arrays.copyOf(array, array.length));


                  You can also modify the code in Person constructor to achieve the same results:



                  public Person(int[] arrayTest) 
                  this.arrayTest = java.util.Arrays.copyOf(arrayTest, arrayTest.length);







                  share|improve this answer














                  share|improve this answer



                  share|improve this answer








                  edited 1 hour ago

























                  answered 1 hour ago









                  Aniket SahrawatAniket Sahrawat

                  6,32121339




                  6,32121339























                      3














                      There is no such thing as immutable (unchangeable) array in Java. The Java language does not support this, and neither does the JVM. You can't solve this at the language level.



                      In general, the only way to prevent changes to an array is to not share the reference to the array with other code that might change it.



                      In your example, you have what is known as a leaky abstraction. You are passing an array to your Person class, and the caller is keeping a reference to that array so that it can change it. To solve this, you can:



                      • copy the array, and pass a reference to the copy, or

                      • have the constructor (or a setter for the array attribute) make the copy.

                      (See answer https://stackoverflow.com/a/55428214/139985 for example code.)



                      The second alternative is preferable from an OO perspective. The Person class should be responsible for preserving its own internal state from interference ... if that is your design requirement. It should not rely on the caller to do this. (Even if the caller is technically part of the same class as is the case here.)






                      share|improve this answer





























                        3














                        There is no such thing as immutable (unchangeable) array in Java. The Java language does not support this, and neither does the JVM. You can't solve this at the language level.



                        In general, the only way to prevent changes to an array is to not share the reference to the array with other code that might change it.



                        In your example, you have what is known as a leaky abstraction. You are passing an array to your Person class, and the caller is keeping a reference to that array so that it can change it. To solve this, you can:



                        • copy the array, and pass a reference to the copy, or

                        • have the constructor (or a setter for the array attribute) make the copy.

                        (See answer https://stackoverflow.com/a/55428214/139985 for example code.)



                        The second alternative is preferable from an OO perspective. The Person class should be responsible for preserving its own internal state from interference ... if that is your design requirement. It should not rely on the caller to do this. (Even if the caller is technically part of the same class as is the case here.)






                        share|improve this answer



























                          3












                          3








                          3







                          There is no such thing as immutable (unchangeable) array in Java. The Java language does not support this, and neither does the JVM. You can't solve this at the language level.



                          In general, the only way to prevent changes to an array is to not share the reference to the array with other code that might change it.



                          In your example, you have what is known as a leaky abstraction. You are passing an array to your Person class, and the caller is keeping a reference to that array so that it can change it. To solve this, you can:



                          • copy the array, and pass a reference to the copy, or

                          • have the constructor (or a setter for the array attribute) make the copy.

                          (See answer https://stackoverflow.com/a/55428214/139985 for example code.)



                          The second alternative is preferable from an OO perspective. The Person class should be responsible for preserving its own internal state from interference ... if that is your design requirement. It should not rely on the caller to do this. (Even if the caller is technically part of the same class as is the case here.)






                          share|improve this answer















                          There is no such thing as immutable (unchangeable) array in Java. The Java language does not support this, and neither does the JVM. You can't solve this at the language level.



                          In general, the only way to prevent changes to an array is to not share the reference to the array with other code that might change it.



                          In your example, you have what is known as a leaky abstraction. You are passing an array to your Person class, and the caller is keeping a reference to that array so that it can change it. To solve this, you can:



                          • copy the array, and pass a reference to the copy, or

                          • have the constructor (or a setter for the array attribute) make the copy.

                          (See answer https://stackoverflow.com/a/55428214/139985 for example code.)



                          The second alternative is preferable from an OO perspective. The Person class should be responsible for preserving its own internal state from interference ... if that is your design requirement. It should not rely on the caller to do this. (Even if the caller is technically part of the same class as is the case here.)







                          share|improve this answer














                          share|improve this answer



                          share|improve this answer








                          edited 36 mins ago

























                          answered 55 mins ago









                          Stephen CStephen C

                          525k72585944




                          525k72585944



























                              draft saved

                              draft discarded
















































                              Thanks for contributing an answer to Stack Overflow!


                              • Please be sure to answer the question. Provide details and share your research!

                              But avoid


                              • Asking for help, clarification, or responding to other answers.

                              • Making statements based on opinion; back them up with references or personal experience.

                              To learn more, see our tips on writing great answers.




                              draft saved


                              draft discarded














                              StackExchange.ready(
                              function ()
                              StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55428172%2fhow-to-prevent-changing-the-value-of-variable%23new-answer', 'question_page');

                              );

                              Post as a guest















                              Required, but never shown





















































                              Required, but never shown














                              Required, but never shown












                              Required, but never shown







                              Required, but never shown

































                              Required, but never shown














                              Required, but never shown












                              Required, but never shown







                              Required, but never shown







                              Popular posts from this blog

                              名間水力發電廠 目录 沿革 設施 鄰近設施 註釋 外部連結 导航菜单23°50′10″N 120°42′41″E / 23.83611°N 120.71139°E / 23.83611; 120.7113923°50′10″N 120°42′41″E / 23.83611°N 120.71139°E / 23.83611; 120.71139計畫概要原始内容臺灣第一座BOT 模式開發的水力發電廠-名間水力電廠名間水力發電廠 水利署首件BOT案原始内容《小檔案》名間電廠 首座BOT水力發電廠原始内容名間電廠BOT - 經濟部水利署中區水資源局

                              Prove that NP is closed under karp reduction?Space(n) not closed under Karp reductions - what about NTime(n)?Class P is closed under rotation?Prove or disprove that $NL$ is closed under polynomial many-one reductions$mathbfNC_2$ is closed under log-space reductionOn Karp reductionwhen can I know if a class (complexity) is closed under reduction (cook/karp)Check if class $PSPACE$ is closed under polyonomially space reductionIs NPSPACE also closed under polynomial-time reduction and under log-space reduction?Prove PSPACE is closed under complement?Prove PSPACE is closed under union?

                              Is my guitar’s action too high? Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern)Strings too stiff on a recently purchased acoustic guitar | Cort AD880CEIs the action of my guitar really high?Μy little finger is too weak to play guitarWith guitar, how long should I give my fingers to strengthen / callous?When playing a fret the guitar sounds mutedPlaying (Barre) chords up the guitar neckI think my guitar strings are wound too tight and I can't play barre chordsF barre chord on an SG guitarHow to find to the right strings of a barre chord by feel?High action on higher fret on my steel acoustic guitar