Cannot assign to this expression
The compiler detected an expression in the position normally held by an lvalue for assignment. This error usually occurs when an expression is being assigned a value but the expression is not capable of accepting the assignment.
The following example illustrates this error:
public class Simple {
public void method1() {
int x = 0;
int y = 1;
x++ = y; //error: '++' not valid
}
}