comparable and comparator java example

1. What is difference between comparable and comparator in Java with example?
2. What is comparable and comparator?
3. What is comparator in Java with example?
4. What is difference between compare and compareTo in Java?
5. What does Comparable do in Java?
6. What is the advantage of generic collection in Java?
7. Where is comparator and comparable used?
8. What is the need of comparator?
9. How do you sort an ArrayList?
10. Which is the example of comparator?
11. Why is string immutable in Java?
12. Can we sort HashMap in Java?

What is difference between comparable and comparator in Java with example?

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 comparable and 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 comparator in Java with example?

Java Comparator interface. ... This interface is found in java. util package and contains 2 methods compare(Object obj1,Object obj2) and equals(Object element). It provides multiple sorting sequences, i.e., you can sort the elements on the basis of any data member, for example, rollno, name, age or anything else.

What is difference between compare and compareTo in Java?

compareTo() is called on one object, to compare it to another object. compare() is called on some object to compare two other objects. The difference is where the logic that does actual comparison is defined.

What does Comparable do 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 advantage of generic collection in Java?

Code that uses generics has many benefits over non-generic code: Stronger type checks at compile time. A Java compiler applies strong type checking to generic code and issues errors if the code violates type safety. Fixing compile-time errors is easier than fixing runtime errors, which can be difficult to find.

Where is comparator and comparable used?

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 the need of comparator?

Comparators are used to find-out deviation of dimensions between a given component being checked and a known datum. The indicated difference in the dimensions is usually small and hence suitable magnification device should be employed to obtain the desired accuracy of measurements.

How do you sort an ArrayList?

To sort the ArrayList, you need to simply call the Collections. sort() method passing the ArrayList object populated with country names. This method will sort the elements (country names) of the ArrayList using natural ordering (alphabetically in ascending order). Lets's write some code for it.

Which is the example of comparator?

For example, lets say we have an Author class has data members: Author name, book name and author age, now if we want to sort the objects based on any of the data member then we can use Comparable but what if we want to have multiple sort choices and we can sort objects based on any choice, this can be done using ...

Why is string immutable in Java?

The string is Immutable in Java because String objects are cached in the String pool. ... Mutable String would produce two different hashcodes at the time of insertion and retrieval if contents of String was modified after insertion, potentially losing the value object in the map.

Can we sort HashMap in Java?

Java HashMap does not preserve any order by default. If there is a need to sort HashMap we sort it explicitly based on the requirements. Java provides an option to sort HashMap based on keys and values.