Arraylist contains object

Sep 27, 2017 · Checking if arraylist contains an object with an attribute [duplicate] The problem. The reason why your approach did not work is because the List#contains ( documentation) method uses the... Iterating manually. We manually iterate the list and check every entry regarding the relevant parameters. ... May 16, 2022 · ArrayList contains() method in Java is used for checking if the specified element exists in the given list or not. Syntax: public boolean contains(Object) object-element to be searched for To perform this search, depending on your class, you can call either the ArrayList.Contains() or the List<>.Contains() method. The syntax of the System.Collections.ArrayList.Contains() method is: public virtual bool Contains(object value); The syntax of the System.Collections.Generic.List<>.Contains() method is: public bool Contains(T value); Sep 30, 2016 · As a result, we can declare an ArrayList object as any of the ways that follow: Collection<String> collection= new ArrayList<> (); List<String> list= new ArrayList<> (); ArrayList<String> alist= new ArrayList<> (); Figure 1: An ArrayList chart. Refer to the Java API Documentation for more details on the classification. To check if ArrayList contains a specific object or element, use ArrayList.contains () method. You can call contains () method on the ArrayList, with the element passed as argument to the method. contains () method returns true if the object is present in the list, else the method returns false. ArrayList.contains () – Reference to Syntax and Examples. Below is the syntax of the contains () method, defined in ArrayList class: This method takes one object as its parameter. It checks if this object is in the ArrayList or not.It returns one boolean value. If the ArrayList contains at least one element, then it returns true. Else it returns false.May 16, 2022 · ArrayList contains() method in Java is used for checking if the specified element exists in the given list or not. Syntax: public boolean contains(Object) object-element to be searched for ArrayList.contains () returns true if this list contains the specified element/object. If the element is not present in this ArrayList, then contains () returns false. Syntax The syntax of contains () method is ArrayList.contains (Object obj) where Returns The method returns boolean value. Example 1 - contains (obj)The syntax of the contains () method is: arraylist.contains (Object obj) Here, arraylist is an object of the ArrayList class. contains () Parameter The contains () method takes a single parameter. obj - element that is checked if present in the arraylist contains () Return Value returns true if the specified element is present in the arraylist.This is how you declare an ArrayList of Integer values. You can do the same to create an ArrayList with String objects as well, e.g. ArrayList<String> cities = new ArrayList<> ( Arrays. asList("London", "Tokyo", "New York")); Similarly here is how you should create ArrayList with float values: It is present in java.util package. We will discuss if an ArrayList can contain multiple references to the same object in Java. The ArrayList in java does not provide the checks for duplicate references to the same object. Therefore, we can insert the same object or reference to a single object as many times as we want.Object obj - represents the object to be checked whether exists or not exists in this Arraylist. Return value: The return type of this method is boolean , it returns true if the given object exists in this Arraylist otherwise, it returns false when the given object does not exist in this Arraylist.I do not want to use a loop and I do not want to overwrite arrayList.contains(). I was expecting .contains() to iterate through my list of TeamMember's and return true when it found one that was equal to the Object passed. The two Objects are equal, but the .contains() method is returning false.Remove duplicate items from an ArrayList: 9.11.34. Removing All Elements: 9.11.35. Looping through a Collection object: while loop, iterator, and for each: 9.11.36. If an ArrayList contains a given item: 9.11.37. Search an element of ArrayList with indexOf and lastIndexOf: 9.11.38. Get container with Iterator from ArrayList ArrayList contains () method is used for checking the specified element existence in the given list. public boolean contains (Object element) It returns true if the specified element is found in the list else it gives false. ExampleThis method determines equality by calling Object.Equals. Starting with the .NET Framework 2.0, this method uses the collection's objects' Equals and CompareTo methods on item to determine whether item exists. In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item ... Syntax: public boolean contains (Object) object-element to be searched for. It returns true if the specified element is found in the list else it returns false. Code#1: Demonstrate the working of the method contains () in integer. Code#2: Demonstrate the working of the method contains () in string. In search operations, we can check if a given ...Remove duplicate items from an ArrayList: 9.11.34. Removing All Elements: 9.11.35. Looping through a Collection object: while loop, iterator, and for each: 9.11.36. If an ArrayList contains a given item: 9.11.37. Search an element of ArrayList with indexOf and lastIndexOf: 9.11.38. Get container with Iterator from ArrayList This method determines equality by calling Object.Equals. Starting with the .NET Framework 2.0, this method uses the collection's objects' Equals and CompareTo methods on item to determine whether item exists. In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item ... The syntax of the contains () method is: arraylist.contains (Object obj) Here, arraylist is an object of the ArrayList class. contains () Parameter The contains () method takes a single parameter. obj - element that is checked if present in the arraylist contains () Return Value returns true if the specified element is present in the arraylist.ArrayList contains () Method in Java ArrayList contains () method checks if the list has the specified element or not. Technically, it returns true only when the list contains at least one element where the following condition is met. (o == null ? e== null : e.equals (o)), where e is each element in the list.Simply iterating over the list looking for the element which satisfies a certain condition is O (n), but so is ArrayList.Contains if you could implement the Equals method. If you're not doing this in loops or inner loops this approach is probably just fine. If you really need very efficient look-up speeds at all cost, you'll need to do two things:Apr 29, 2013 · List#contains () method uses the equals () method to evaluate if two objects are the same. So, you need to override equals () in your Class A and also override the hashCode (). @Override public boolean equals (Object object) { boolean isEqual= false; if (object != null && object instanceof A) { isEqual = (this.elementA == ( (A) object).elementA); } return isEqual; } @Override public int hashCode () { return this.elementA; } List<Integer> list = new ArrayList <Integer> (); It is more common to create an ArrayList of definite type such as Integer, Double, etc. But there is also a method to create ArrayLists that are capable of holding Objects of multiple Types. We will discuss how we can use the Object class to create an ArrayList.ArrayList<Integer> myNum = new ArrayList<Integer>(); Notes: You specify the type you will store in the ArrayList in <>’s. ArrayList can only hold items of a single type. ArrayLists must be of OBJECTS. If you want an arraylist of primitive types you must use the object wrapper (int -> Integer, double -> Double etc). ArrayList.Contains (Object) method determines whether the element exists in ArrayList or not. Properties of ArrayList Class: Elements can be added or removed from the Array List collection at any point in time. The ArrayList is not guaranteed to be sorted. The capacity of an ArrayList is the number of elements the ArrayList can hold.To check if ArrayList contains a specific object or element, use ArrayList.contains () method. You can call contains () method on the ArrayList, with the element passed as argument to the method. contains () method returns true if the object is present in the list, else the method returns false.To perform this search, depending on your class, you can call either the ArrayList.Contains() or the List<>.Contains() method. The syntax of the System.Collections.ArrayList.Contains() method is: public virtual bool Contains(object value); The syntax of the System.Collections.Generic.List<>.Contains() method is: public bool Contains(T value); If you are using Java 8 then use predicate. in predicte you can filter arraylist with given criteria and then check if the resultant arraylist size is zero or not. thus you can find object with prooerty is there or not. Share answered Sep 27, 2017 at 10:18 Ganesh Toni 36 3 Add a comment 0Answer: An ArrayList is an implementation of the List interface. An ArrayList is backed by an array, where the objects are stored. If an element is added even though the backing array is full, a new, larger array is created and the elements in the old array are aged in the new array. Afterwards t...Oct 23, 2019 · Here’s a short example to convert an ArrayList of integers, numbersList, to int array. Integer[] array = numbersList.toArray(new Integer[0]); Replace Integer with the type of ArrayList you’re trying to convert to array and it’ll work E.g. for String: String[] array = strList.toArray(new String[0]); What’s with the weird-looking argument ... Sep 27, 2017 · Checking if arraylist contains an object with an attribute [duplicate] The problem. The reason why your approach did not work is because the List#contains ( documentation) method uses the... Iterating manually. We manually iterate the list and check every entry regarding the relevant parameters. ... Syntax: import java.util.*; ArrayList<data_type> arrayList = new ArrayList<> (); ArrayList<data_type> list_name = new ArrayList<> (int capacity); The above given is the syntax for array list creation in java, the array list needs to be created with the arraylist keyword as the first item. The array list forms the first item and then the data ... ArrayList contains () Method in Java ArrayList contains () method checks if the list has the specified element or not. Technically, it returns true only when the list contains at least one element where the following condition is met. (o == null ? e== null : e.equals (o)), where e is each element in the list.Object obj - represents the object to be checked whether exists or not exists in this Arraylist. Return value: The return type of this method is boolean , it returns true if the given object exists in this Arraylist otherwise, it returns false when the given object does not exist in this Arraylist.To perform this search, depending on your class, you can call either the ArrayList.Contains() or the List<>.Contains() method. The syntax of the System.Collections.ArrayList.Contains() method is: public virtual bool Contains(object value); The syntax of the System.Collections.Generic.List<>.Contains() method is: public bool Contains(T value); Module 12 ArrayList 18 COMP2026 – Problem Solving Using Object Oriented Programming Dr. Joe C.K. YAU ArrayList – Other Popular Methods • aList.clear() – remove all elements from the list • aList.isEmpty() – return true if the list is empty • aList.contains(obj) – return true if the list contains obj • aList.indexOf(obj ... Java ArrayList contains() 方法 Java ArrayList contains() 方法用于判断元素是否在动态数组中。 contains() 方法的语法为: arraylist.contains(Object obj) 注:arraylist 是 ArrayList 类的一个对象。 参数说明: obj - 要检测的元素 返回值 如果指定的元素存在于动态数组中,则返回 true。Parameters: C# ArrayList Contains() has the following parameters: . value - The object to locate in the System.Collections.IList.; Return. true if the System.Object is found in the System.Collections.IList; otherwise, false. Example The following examples show how to use C# ArrayList.Method 2: Using indexOf () method. Contains () method uses indexOf () method to determine if a specified element is present in the list or not. So we can also directly use the indexOf () method to check the existence of any supplied element value. Java. import java.io.*;ArrayList ( Collection <? extends E > c) Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator. ArrayList (int initialCapacity) Constructs an empty list with the specified initial capacity. Method Summary Methods inherited from class java.util. AbstractListArrayList ( Collection <? extends E > c) Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator. ArrayList (int initialCapacity) Constructs an empty list with the specified initial capacity. Method Summary Methods inherited from class java.util. AbstractListApr 29, 2013 · List#contains () method uses the equals () method to evaluate if two objects are the same. So, you need to override equals () in your Class A and also override the hashCode (). @Override public boolean equals (Object object) { boolean isEqual= false; if (object != null && object instanceof A) { isEqual = (this.elementA == ( (A) object).elementA); } return isEqual; } @Override public int hashCode () { return this.elementA; } Sep 21, 2019 · The ArrayList collection accepts null as a valid value, an allows duplicate elements. 2. How to add an item to a C# ArrayList. The Add method on ArrayList appends a new item/element object to the end of the ArrayList. You can add elements in the ArrayList until memory runs out. The objects are stored in the managed heap. It is present in java.util package. We will discuss if an ArrayList can contain multiple references to the same object in Java. The ArrayList in java does not provide the checks for duplicate references to the same object. Therefore, we can insert the same object or reference to a single object as many times as we want.7 Answers Sorted by: 33 List#contains () method uses the equals () method to evaluate if two objects are the same. So, you need to override equals () in your Class A and also override the hashCode ().JavaScript has a built in array constructor new Array (). But you can safely use [] instead. These two different statements both create a new empty array named points: const points = new Array (); const points = []; These two different statements both create a new array containing 6 numbers: const points = new Array (40, 100, 1, 5, 25, 10); May 16, 2022 · ArrayList contains() method in Java is used for checking if the specified element exists in the given list or not. Syntax: public boolean contains(Object) object-element to be searched for May 16, 2022 · ArrayList contains() method in Java is used for checking if the specified element exists in the given list or not. Syntax: public boolean contains(Object) object-element to be searched for ArrayList<Integer> myNum = new ArrayList<Integer>(); Notes: You specify the type you will store in the ArrayList in <>’s. ArrayList can only hold items of a single type. ArrayLists must be of OBJECTS. If you want an arraylist of primitive types you must use the object wrapper (int -> Integer, double -> Double etc). Answer: An ArrayList is an implementation of the List interface. An ArrayList is backed by an array, where the objects are stored. If an element is added even though the backing array is full, a new, larger array is created and the elements in the old array are aged in the new array. Afterwards t...Oct 23, 2019 · Here’s a short example to convert an ArrayList of integers, numbersList, to int array. Integer[] array = numbersList.toArray(new Integer[0]); Replace Integer with the type of ArrayList you’re trying to convert to array and it’ll work E.g. for String: String[] array = strList.toArray(new String[0]); What’s with the weird-looking argument ... The java.util.ArrayList.contains () method can be used to check if a Java ArrayList contains a given item or not. This method has a single parameter i.e. the item whose presence in the ArrayList is tested. Also it returns true if the item is present in the ArrayList and false if the item is not present.I do not want to use a loop and I do not want to overwrite arrayList.contains(). I was expecting .contains() to iterate through my list of TeamMember's and return true when it found one that was equal to the Object passed. The two Objects are equal, but the .contains() method is returning false.ArrayList<Integer> myNum = new ArrayList<Integer>(); Notes: You specify the type you will store in the ArrayList in <>’s. ArrayList can only hold items of a single type. ArrayLists must be of OBJECTS. If you want an arraylist of primitive types you must use the object wrapper (int -> Integer, double -> Double etc). 7 Answers Sorted by: 33 List#contains () method uses the equals () method to evaluate if two objects are the same. So, you need to override equals () in your Class A and also override the hashCode ().Module 12 ArrayList 18 COMP2026 – Problem Solving Using Object Oriented Programming Dr. Joe C.K. YAU ArrayList – Other Popular Methods • aList.clear() – remove all elements from the list • aList.isEmpty() – return true if the list is empty • aList.contains(obj) – return true if the list contains obj • aList.indexOf(obj ... The syntax of the contains () method is: arraylist.contains (Object obj) Here, arraylist is an object of the ArrayList class. contains () Parameter The contains () method takes a single parameter. obj - element that is checked if present in the arraylist contains () Return Value returns true if the specified element is present in the arraylist.7 Answers Sorted by: 33 List#contains () method uses the equals () method to evaluate if two objects are the same. So, you need to override equals () in your Class A and also override the hashCode ().If you are using Java 8 then use predicate. in predicte you can filter arraylist with given criteria and then check if the resultant arraylist size is zero or not. thus you can find object with prooerty is there or not. Share answered Sep 27, 2017 at 10:18 Ganesh Toni 36 3 Add a comment 0Object obj - represents the object to be checked whether exists or not exists in this Arraylist. Return value: The return type of this method is boolean , it returns true if the given object exists in this Arraylist otherwise, it returns false when the given object does not exist in this Arraylist.May 16, 2022 · ArrayList contains() method in Java is used for checking if the specified element exists in the given list or not. Syntax: public boolean contains(Object) object-element to be searched for JavaScript has a built in array constructor new Array (). But you can safely use [] instead. These two different statements both create a new empty array named points: const points = new Array (); const points = []; These two different statements both create a new array containing 6 numbers: const points = new Array (40, 100, 1, 5, 25, 10); Each ArrayList instance has a capacity. The capacity is the size of the array used to store the elements in the list. ... Collection.contains(Object) listIterator public ListIterator<E> listIterator(int index) Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list.ArrayList.Contains (Object) method determines whether the element exists in ArrayList or not. Properties of ArrayList Class: Elements can be added or removed from the Array List collection at any point in time. The ArrayList is not guaranteed to be sorted. The capacity of an ArrayList is the number of elements the ArrayList can hold.Module 12 ArrayList 18 COMP2026 – Problem Solving Using Object Oriented Programming Dr. Joe C.K. YAU ArrayList – Other Popular Methods • aList.clear() – remove all elements from the list • aList.isEmpty() – return true if the list is empty • aList.contains(obj) – return true if the list contains obj • aList.indexOf(obj ... Sep 21, 2019 · The ArrayList collection accepts null as a valid value, an allows duplicate elements. 2. How to add an item to a C# ArrayList. The Add method on ArrayList appends a new item/element object to the end of the ArrayList. You can add elements in the ArrayList until memory runs out. The objects are stored in the managed heap. The java.util.ArrayList.contains(Object) method returns true if this list contains the specified element. Declaration Following is the declaration for java.util.ArrayList.contains() methodSep 21, 2019 · The ArrayList collection accepts null as a valid value, an allows duplicate elements. 2. How to add an item to a C# ArrayList. The Add method on ArrayList appends a new item/element object to the end of the ArrayList. You can add elements in the ArrayList until memory runs out. The objects are stored in the managed heap. ArrayList.contains () returns true if this list contains the specified element/object. If the element is not present in this ArrayList, then contains () returns false. Syntax The syntax of contains () method is ArrayList.contains (Object obj) where Returns The method returns boolean value. Example 1 - contains (obj)The Java ArrayList containsAll () method checks whether the arraylist contains all the elements of the specified collection. The syntax of the containsAll () method is: arraylist.containsAll (Collection c); Here, arraylist is an object of the ArrayList class.Java ArrayList.contains() Method with example: The contains() method is used to determines whether an element exists in a ArrayList object. Returns true if this list contains the specified element.Below is the syntax of the contains () method, defined in ArrayList class: This method takes one object as its parameter. It checks if this object is in the ArrayList or not.It returns one boolean value. If the ArrayList contains at least one element, then it returns true. Else it returns false.Syntax: public boolean contains (Object) object-element to be searched for. It returns true if the specified element is found in the list else it returns false. Code#1: Demonstrate the working of the method contains () in integer. Code#2: Demonstrate the working of the method contains () in string. In search operations, we can check if a given ...Syntax: import java.util.*; ArrayList<data_type> arrayList = new ArrayList<> (); ArrayList<data_type> list_name = new ArrayList<> (int capacity); The above given is the syntax for array list creation in java, the array list needs to be created with the arraylist keyword as the first item. The array list forms the first item and then the data ... To check if ArrayList contains a specific object or element, use ArrayList.contains () method. You can call contains () method on the ArrayList, with the element passed as argument to the method. contains () method returns true if the object is present in the list, else the method returns false.May 16, 2022 · ArrayList contains() method in Java is used for checking if the specified element exists in the given list or not. Syntax: public boolean contains(Object) object-element to be searched for List<Integer> list = new ArrayList <Integer> (); It is more common to create an ArrayList of definite type such as Integer, Double, etc. But there is also a method to create ArrayLists that are capable of holding Objects of multiple Types. We will discuss how we can use the Object class to create an ArrayList.Nov 12, 2021 · The example adds elements to an array list one by one. List<String> langs = new ArrayList<> (); An ArrayList is created. The data type specified inside the diamond brackets (< >) restricts the elements to this data type; in our case, we have a list of strings. langs.add ("Java"); An element is appended at the end of the list with the add method. Module 12 ArrayList 18 COMP2026 – Problem Solving Using Object Oriented Programming Dr. Joe C.K. YAU ArrayList – Other Popular Methods • aList.clear() – remove all elements from the list • aList.isEmpty() – return true if the list is empty • aList.contains(obj) – return true if the list contains obj • aList.indexOf(obj ... Jan 11, 2020 · To create an array list in Java, you declare an ArrayList variable and call the ArrayList constructor to instantiate an ArrayList object and assign it to the variable: ArrayList friends = new ArrayList(); You can optionally specific a capacity in the ArrayList constructor: ArrayList friends = new ArrayList(100); Click to see full answer. The java.util.ArrayList.contains () method can be used to check if a Java ArrayList contains a given item or not. This method has a single parameter i.e. the item whose presence in the ArrayList is tested. Also it returns true if the item is present in the ArrayList and false if the item is not present.Jan 11, 2020 · To create an array list in Java, you declare an ArrayList variable and call the ArrayList constructor to instantiate an ArrayList object and assign it to the variable: ArrayList friends = new ArrayList(); You can optionally specific a capacity in the ArrayList constructor: ArrayList friends = new ArrayList(100); Click to see full answer. Each ArrayList instance has a capacity. The capacity is the size of the array used to store the elements in the list. ... Collection.contains(Object) listIterator public ListIterator<E> listIterator(int index) Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list.Answer: An ArrayList is an implementation of the List interface. An ArrayList is backed by an array, where the objects are stored. If an element is added even though the backing array is full, a new, larger array is created and the elements in the old array are aged in the new array. Afterwards t...The java.util.ArrayList.contains () method can be used to check if a Java ArrayList contains a given item or not. This method has a single parameter i.e. the item whose presence in the ArrayList is tested. Also it returns true if the item is present in the ArrayList and false if the item is not present.It is present in java.util package. We will discuss if an ArrayList can contain multiple references to the same object in Java. The ArrayList in java does not provide the checks for duplicate references to the same object. Therefore, we can insert the same object or reference to a single object as many times as we want.Nov 12, 2021 · The example adds elements to an array list one by one. List<String> langs = new ArrayList<> (); An ArrayList is created. The data type specified inside the diamond brackets (< >) restricts the elements to this data type; in our case, we have a list of strings. langs.add ("Java"); An element is appended at the end of the list with the add method. Jan 11, 2020 · To create an array list in Java, you declare an ArrayList variable and call the ArrayList constructor to instantiate an ArrayList object and assign it to the variable: ArrayList friends = new ArrayList(); You can optionally specific a capacity in the ArrayList constructor: ArrayList friends = new ArrayList(100); Click to see full answer. Sep 30, 2016 · As a result, we can declare an ArrayList object as any of the ways that follow: Collection<String> collection= new ArrayList<> (); List<String> list= new ArrayList<> (); ArrayList<String> alist= new ArrayList<> (); Figure 1: An ArrayList chart. Refer to the Java API Documentation for more details on the classification. May 16, 2022 · ArrayList contains() method in Java is used for checking if the specified element exists in the given list or not. Syntax: public boolean contains(Object) object-element to be searched for Sep 27, 2017 · Checking if arraylist contains an object with an attribute [duplicate] The problem. The reason why your approach did not work is because the List#contains ( documentation) method uses the... Iterating manually. We manually iterate the list and check every entry regarding the relevant parameters. ... This method determines equality by calling Object.Equals. Starting with the .NET Framework 2.0, this method uses the collection's objects' Equals and CompareTo methods on item to determine whether item exists. In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item ...To check if ArrayList contains a specific object or element, use ArrayList.contains () method. You can call contains () method on the ArrayList, with the element passed as argument to the method. contains () method returns true if the object is present in the list, else the method returns false.To perform this search, depending on your class, you can call either the ArrayList.Contains() or the List<>.Contains() method. The syntax of the System.Collections.ArrayList.Contains() method is: public virtual bool Contains(object value); The syntax of the System.Collections.Generic.List<>.Contains() method is: public bool Contains(T value); ArrayList ( Collection <? extends E > c) Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator. ArrayList (int initialCapacity) Constructs an empty list with the specified initial capacity. Method Summary Methods inherited from class java.util. AbstractListThe syntax of the contains () method is: arraylist.contains (Object obj) Here, arraylist is an object of the ArrayList class. contains () Parameter The contains () method takes a single parameter. obj - element that is checked if present in the arraylist contains () Return Value returns true if the specified element is present in the arraylist.Object obj - represents the object to be checked whether exists or not exists in this Arraylist. Return value: The return type of this method is boolean , it returns true if the given object exists in this Arraylist otherwise, it returns false when the given object does not exist in this Arraylist.Each ArrayList instance has a capacity. The capacity is the size of the array used to store the elements in the list. ... Collection.contains(Object) listIterator public ListIterator<E> listIterator(int index) Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list.7 Answers Sorted by: 33 List#contains () method uses the equals () method to evaluate if two objects are the same. So, you need to override equals () in your Class A and also override the hashCode ().Below is the syntax of the contains () method, defined in ArrayList class: This method takes one object as its parameter. It checks if this object is in the ArrayList or not.It returns one boolean value. If the ArrayList contains at least one element, then it returns true. Else it returns false.Apr 29, 2013 · List#contains () method uses the equals () method to evaluate if two objects are the same. So, you need to override equals () in your Class A and also override the hashCode (). @Override public boolean equals (Object object) { boolean isEqual= false; if (object != null && object instanceof A) { isEqual = (this.elementA == ( (A) object).elementA); } return isEqual; } @Override public int hashCode () { return this.elementA; } Sep 27, 2017 · Checking if arraylist contains an object with an attribute [duplicate] The problem. The reason why your approach did not work is because the List#contains ( documentation) method uses the... Iterating manually. We manually iterate the list and check every entry regarding the relevant parameters. ... 10l_2ttl