incompatible vs incomparable type

Question

I am confused with these two types of error message in java.

For incompatible types, it might occur in the following scenario

if(integer=="String")

In what scenario will I get a incomparable type in java? Whats the main difference between these two?

Answer 1

Incomparable means that you are trying to compare two different types which is not legal. An example:

Integer i = new Integer(8);
if( i == "Foo" ){}

It will show incomparable types: java.lang.Integer and java.lang.String because Java compiler can't compare two different types (in this case Integer and String).

Now incompatible means that the compiler tried to perform a operation over a variable and that variable is incompatible with the operation. An example:

public static String foo(int a){
    return a;
}

Obviously you can't return a int value as a String without a proper cast, return operation in this case needs a String and its been giving and int so return operation is incompatible with int data type.

In short, incompatible refers to data types that can't make a specific operation and incomparable refers to a pair of data types that can't be compared.

Answer 2

In-Compatible types error
Occurs when trying to assign with different type

In-Comparable type error
Occurs when trying to compare two different types

Answer 3

incompaitable types error happens when you try to do the assignments of two incompatible types.

While incomparable type errors happen when you try to compare two different types.