java - Error . operator < cannot be applied -



java - Error . operator < cannot be applied -

in line 11 there error .

operator < cannot applied java.lang.object,java.lang.object

i don't quite understand 1 time again i'm new generics in java . bear me please.

public void sortbykey() { linkedlist temp = new linkedlist(); linkedlist 3rd = new linkedlist(); temp=head; if(temp!=null) { while(temp.next!=null) { if (temp.key < temp.next.key) { third.item = temp.key; temp.key = temp.next.key; temp.next.key = third.item; } else temp = temp.next; } } }

simply, operator can applied on numeric types, such int, byte, double, float, etc , boxing classes (such integer, byte, etc.).

it doesn't work combined generics, because compiler doesn't know exact types of operands. when working generics, these types set @ runtime, after type erasure has occurred.

a possible solution create class of key property implement comparable<t> interface , able compare with:

temp.key.compareto(temp.next.key) > 0

java generics compiler-errors

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