What is comparable interface in Java?

Java Comparable interface is used to order the objects of the user-defined class. This interface is found in java. lang package and contains only one method named compareTo(Object). It provides a single sorting sequence only, i.e., you can sort the elements on the basis of single data member only.

What is the 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.

What does comparable mean in Java?

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 comparable and comparator?

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.

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How does comparable work in Java?

The compareTo() method works by returning an int value that is either positive, negative, or zero. It compares the object by making the call to the object that is the argument. A negative number means that the object making the call is “less” than the argument.

What is the comparable interface used for?

Java Comparable interface is used to order the objects of the user-defined class. This interface is found in java. lang package and contains only one method named compareTo(Object). It provides a single sorting sequence only, i.e., you can sort the elements on the basis of single data member only.

Is comparable a functional interface?

Is it logically a functional interface? No: Comparable doesn’t represent a function. It is more like a trait of an object.

What is the compareTo method?

The compareTo() method compares two strings lexicographically. … The method returns 0 if the string is equal to the other string. A value less than 0 is returned if the string is less than the other string (less characters) and a value greater than 0 if the string is greater than the other string (more characters).

What does the hashCode () method?

The hashCode method is an inbuilt method that returns the integer hashed value of the input value. … If two or more objects are equal according to the equals method, then their hashes should be equal too. If two or more objects are not equal according to the equals method, then their hashes can be equal or unequal.

What is equal method in Java?

The java string equals() method compares the two given strings based on the content of the string. If any character is not matched, it returns false. If all characters are matched, it returns true. The String equals() method overrides the equals() method of Object class.

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What is difference between Array and ArrayList?

An array is basic functionality provided by Java. ArrayList is part of collection framework in Java. Therefore array members are accessed using [], while ArrayList has a set of methods to access elements and modify them. Array is a fixed size data structure while ArrayList is not.

What is a Comparator do?

In electronics, a comparator is a device that compares two voltages or currents and outputs a digital signal indicating which is larger. It has two analog input terminals and and one binary digital output .

How do you use comparable?

The Comparable interface specifies one method, compareTo , that determines how the objects are to be sequenced. This method returns a negative integer, zero, or positive integer to indicate the current object is less than, equal to, or greater than the object passed to method.

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