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How to compare two ArrayList objects in Java?
There are following ways to compare two ArrayList in Java: Java equals () method of List interface compares the specified object with the list for equality. It overrides the equals () method of Object class. This method accepts an object to be compared for equality with the list.
How to tell if two lists are equal in Java?
Returns true iff the given Collection s contain exactly the same elements with exactly the same cardinalities. That is, iff the cardinality of e in a is equal to the cardinality of e in b, for each element e in a or b. Returns: true iff the collections contain the same elements with the same cardinalities.
What’s the best way to sort two lists?
You could sort both lists using Collections.sort () and then use the equals method. A slighly better solution is to first check if they are the same length before ordering, if they are not, then they are not equal, then sort, then use equals.
How to remove all elements from a list in Java?
You may use a java.util.Collection and/or java.util.ArrayList for that. The retainAll method does the following: For the second part ( similar values ) you may use the removeAll method: Removes all of this collection’s elements that are also contained in the specified collection.
When do two lists have the same value?
… In other words, two lists are defined to be equal if they contain the same elements in the same order. It does require you to properly implement equals in your MyData class.
How to compare the content of a list against some condition?
Comparing the content of Lists against some condition is a common use case to handle in many business scenarios. This comparison can be broadly classified as: Comparing each element of a List against some condition. As an example, you have a List of Employee Objects and you need to check that all your Employees are above 18.
How to subtract one list from the other in Java?
You can subtract one list from the other using CollectionUtils.subtract, if the result is an empty collection, it means both lists are the same. Another approach is using CollectionUtils.isSubCollection or CollectionUtils.isProperSubCollection. For any case you should implement equals and hashCode methods for your object.