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  • Writer's picturePuru Uttam

Comparable vs Comparator in Java

These are the two interfaces mainly provided to achieve sorting on the basis of comparisons among the objects on the basis of custom/self imposed conditions.


  • Comparable in Java is used to compare an object with another objects, whereas Comparator is used for comparing different objects.

  • Comparable uses compareTo(arg) method for sorting the data whereas Comparator uses compare(arg1, arg2) method.

  • Comparable is used bydefault when Collections.sort() or Arrays.sort() is used for sorting whereas Comparator needs to be mentioned whenever we are going to use it for sorting.


//comparable
Collections.sort(list)

//comparator
Collections.sort(list,comparator)

  • Comparable is in java.lang package and Comparator is in the java.util package.

  • Comparable modify the actual class but comparator doesn't affect the actual class.

  • Comparable is single sorting technique it means the sorting can be done on the basis of one attribute/element of an object and Comparator is multiple sorting technique which means sorting can be done on the basis of multiple attributes/elements of object.


public class MyEmployees {     
private int id;     
private String name;     
private int salary;          
// constructor, setters, getters   
}

//comparable
public class MyEmployees implements Comparable<MyEmployees> {      @Override
public int compareTo(MyEmployees otherEmployee) {         
return Integer.compare(getSalary(), otherEmployee.getSalary());     
}
}

//comparator
public class MyEmployeesComparator implements Comparator<MyEmployees> {      @Override
public int compare(MyEmployees firstEmployee, MyEmployees secondEmployee) {        
return Integer.compare(firstEmployee.getSalary(), secondEmployee.getSalary()); 
}
}

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