What is the difference between a comparable and a Comparator?

1) Comparable provides a single sorting sequence. In other words, we can sort the collection on the basis of a single element such as id, name, and price. The Comparator provides multiple sorting sequences. In other words, we can sort the collection on the basis of multiple elements such as id, name, and price etc.

What is comparable and Comparator in Java with example?

Logically, Comparable interface compares “this” reference with the object specified and Comparator in Java compares two different class objects provided. If any class implements Comparable interface in Java then collection of that object either List or Array can be sorted automatically by using Collections.

Can you explain difference between compare and compareTo in Java?

compareTo() is from the Comparable interface. compare() is from the Comparator interface. Both methods do the same thing, but each interface is used in a slightly different context. The Comparable interface is used to impose a natural ordering on the objects of the implementing class.

What is a comparable interface in Java?

The Java Comparable interface, java. lang. Comparable , represents an object which can be compared to other objects. For instance, numbers can be compared, strings can be compared using alphabetical comparison etc. Several of the built-in classes in Java implements the Java Comparable interface.

What is the difference between comparable interface and Comparator interface?

Comparable and comparator both are an interface that can be used to sort the elements of the collection. Comparator interface sort collection using two objects provided to it, whereas comparable interface compares” this” refers to the one objects provided to it.

What is Comparator interface?

Method 2: Using comparator interface- Comparator interface is used to order the objects of a user-defined class. This interface is present in java. util package and contains 2 methods compare(Object obj1, Object obj2) and equals(Object element). Using a comparator, we can sort the elements based on data members.

What is comparator and comparable interface?

What is difference between writable comparable and writable comparator?

In short, the type used as key in Hadoop must be a WritableComparable , while the type only used as value could be just a Writable . A Writable which is also Comparable. WritableComparables can be compared to each other, typically via Comparators.

Which is incorrect about Comparator and comparable in Java?

Comparable provides compareTo() method to sort elements in Java whereas Comparator provides compare() method to sort elements in Java. lang package whereas Comparator interface is present in java. util package. Comparable provides single sorting sequence while Comparator provides multiple sorting sequences.

Why use a Comparator if we already have comparable?

Comparable should be used when you compare instances of the same class. Comparator can be used to compare instances of different classes. Comparable is implemented by the class which needs to define a natural ordering for its objects. For example, String implements Comparable.

What is a comparable interface?

The Comparable interface defines the `compareTo` method used to compare objects. If a class implements the Comparable interface, objects created from that class can be sorted using Java’s sorting algorithms. The Comparable interface takes as its type parameter the class that is the subject of the comparison.

Why do we need comparator and comparable in Java?

How to use comparator in Java?

Open your text editor and type in the following Java statements: Notice that the class implements Comparable.

How do I create an interface in Java?

The New Java Interface wizard can be used to create a new java interface. Clicking on the File menu and selecting New → Interface. Right clicking in the package explorer and selecting New > Interface. Clicking on the class drop down button () in the tool bar and selecting Interface ().

What is the purpose of interfaces in Java?

The Purpose of Java Interfaces. The Java interface construct is borrowed from the Objective-C protocol. It is used to identify a common set of methods for the group of classes that implement the interface. It is also used to share constants between classes.

What is an example of interface in Java?

Interfaces in Java. If a class implements an interface and does not provide method bodies for all functions specified in the interface, then class must be declared abstract. A Java library example is, Comparator Interface. If a class implements this interface, then it can be used to sort a collection.