Methods of the Collection Interface
This interface contains various methods which can be directly used by all the collections which implement this interface. They are:
|
Method |
Description |
|---|---|
| add(Object) | This method is used to add an object to the collection. |
| addAll(Collection c) | This method adds all the elements in the given collection to this collection. |
| clear() | This method removes all of the elements from this collection. |
| contains(Object o) | This method returns true if the collection contains the specified element. |
| containsAll(Collection c) | This method returns true if the collection contains all of the elements in the given collection. |
| equals(Object o) | This method compares the specified object with this collection for equality. |
| hashCode() | This method is used to return the hash code value for this collection. |
| isEmpty() | This method returns true if this collection contains no elements. |
| iterator() | This method returns an iterator over the elements in this collection. |
| max() |
This method is used to return the maximum value present in the collection. |
| parallelStream() | This method returns a parallel Stream with this collection as its source. |
| remove(Object o) | This method is used to remove the given object from the collection. If there are duplicate values, then this method removes the first occurrence of the object. |
| removeAll(Collection c) | This method is used to remove all the objects mentioned in the given collection from the collection. |
| removeIf(Predicate filter) | This method is used to remove all the elements of this collection that satisfy the given predicate. |
| retainAll(Collection c) | This method is used to retain only the elements in this collection that are contained in the specified collection. |
| size() | This method is used to return the number of elements in the collection. |
| spliterator() | This method is used to create a Spliterator over the elements in this collection. |
| stream() | This method is used to return a sequential Stream with this collection as its source. |
| toArray() | This method is used to return an array containing all of the elements in this collection. |
Collections in Java
Any group of individual objects that are represented as a single unit is known as a Java Collection of Objects. In Java, a separate framework named the “Collection Framework” has been defined in JDK 1.2 which holds all the Java Collection Classes and Interface in it.
In Java, the Collection interface (java.util.Collection) and Map interface (java.util.Map) are the two main “root” interfaces of Java collection classes.
What You Should Learn in Java Collections?
- SortedSet Interface
- Map Interface
- Other Important Concepts