Java overload return type

Overload with different return type in java

To make this concrete, say you have this interface: The following is legal because the return type is a subclass of Number: Because overloaded methods (which have the same name but different signatures) are effectively different methods, you are free to use different return types if you like . however . Solution 1: Beginning with Java 5, covariant return types are allowed for overridden methods .

Why I need different return types, when overloading generic methods

Overloading, simply said, means to have two or more methods with the same name but with a different signature .

The signature of a method consists of the methods name and the parameters. When overloading methods, obviously the names will be the same, which means that the overloaded methods differ only with the parameters list they have.

The return-type has nothing to do with method overloading!

The relationship of overload and method return type in Java?, First and important rule to overload a method in java is to change method signature. · Return type of method is never part of method signature,

Java Overloading methods (Different return types)

Java Source Code here:http://ramj2ee.blogspot.com/2016/02/java-tutorial-java-overloading Duration: 1:26

Can a method be overloaded with another which returns a subclass?

Beginning with Java 5, covariant return types are allowed for overridden methods . This means that an overridden method in a subclass is allowed to use a signature which returns a type that may be a subclass of the parent signature’s return type.

To make this concrete, say you have this interface:

public interface MyInterface

The following is legal because the return type is a subclass of Number:

public class MyClass implements MyInterface < : : @Override public Integer apply(double op1, double op2) < : : return Integer.valueOf(result); >> 

Because overloaded methods (which have the same name but different signatures) are effectively different methods, you are free to use different return types if you like . however . this is discouraged because methods that have the same name but different return types can be confusing to programmers and can complicate the use of your API. It’s best not to overload mrthods when you can reasonably avoid it.

public Object foo() public String foo(int a)

as long as the two methods get different set of variables, there’s no problem with returning different types (even if they are not subclass).

The logic is very simple — if the compiler can choose without doubt which one to use — there’s no issue. In this case- if you give the method int it’s one method, and without parameters it’s the other, no dilema (and the same name does not matter here)

public Object foo() public String foo()

This one is not valid, since here the compiler can’t ‘choose’ which one to use.

Yes, and it does not even need to be a subclass foo() , and foo(int) are two completely different and unrelated functions as far as the compiler is concerned, each can have any return type you want.

Is overloading a method with different access modifier, return type, If two methods of a class (whether both declared in the same class, or both inherited by a class, or one declared and one inherited) have the

Must two overloading methods have same return value, to be called «overloading»?

CAN’T we call the two functions above «overloading»?

We can call it overloading, because the methods have different parameter types.

In the JLS, overloading is defined as:

If two methods of a class (whether both declared in the same class, or both inherited by a class, or one declared and one inherited) have the same name but signatures that are not override-equivalent, then the method name is said to be overloaded.

«Override-equivalent signatures» basically means «same signatures when type erasure is taken into account» (Learn more here).

The signature of a method doesn’t include the return type:

Two methods or constructors, M and N, have the same signature if they have the same name, the same type parameters (if any) (§8.4.4), and, after adapting the formal parameter types of N to the the type parameters of M, the same formal parameter types.

I think what the question in the screenshot was getting at, is that you can’t overload methods by only changing the return type. I would say the options are worded rather badly.

same functions headers with different parameters is called overloading , so I think your example is overloading .

and i think it’s about the headers only not the return type .

How to overload function with different return types and the same, I want to overload function with the same parameters (or without parameters at all) and different return types.

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The relationship of overload and method return type in Java?

If there are two methods, they have different parameters, and their return types are different. Like this:

int test(int p) < System.out.println("version one"); return p; >boolean test(boolean p, int q)

If the return types are same, of course this is overload. But since the return types are different, can we regard this as overload still?

@biziclop: that’s what distinguishes overloads from eachother. But it’s just the name that determines they are overloads in the first place.

@JeroenVannevel What I tried to say is that you can’t have two methods with the same name and parameters but different return types. That’s not overloading but a compile error. 🙂

4 Answers 4

The Java programming language supports overloading methods, and Java can distinguish between methods with different method signatures. This means that methods within a class can have the same name if they have different parameter lists (there are some qualifications to this that will be discussed in the lesson titled «Interfaces and Inheritance»).

Having a different return type is inconsequential to overloading. In fact, this is quite common with methods that return one of their arguments. E.g., java.util.Math has a bunch of overloaded max methods. A max of two int s return an int , a max of two double s return a double , etc.

consider following points for overloading:

First and important rule to overload a method in java is to change method signature. Method signature is made of number of arguments, type of arguments and order of arguments if they are of different types.

public class DemoClass < // Overloaded method public Integer sum(Integer a, Integer b) < return a + b; >// Overloading method public Integer sum(Float a, Integer b) < //Valid return null; >> 

public class DemoClass < // Overloaded method public Integer sum(Integer a, Integer b) < return a + b; >// Overloading method public Float sum(Integer a, Integer b) < //Not valid; Compile time error return null; >> 

public class DemoClass < // Overloaded method public Integer sum(Integer a, Integer b) throws NullPointerException< return a + b; >// Overloading method public Integer sum(Integer a, Integer b) throws Exception < //Not valid; Compile time error return null; >> 

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