Java Operator Precedence and Ternary Operator

Question

The code

return "Unexpected Error: " + (e.getMessage() == null ? "No further details!" : e.getMessage());

produces my expected result. For example, for an e IndexOutOfBoundsException, I get

Unexpected Error: Index 0 out of bounds for length 0

However when I remove the extra parentheses surrounding the ternary expression like

return "Unexpected Error: " + e.getMessage() == null ? "No further details!" : e.getMessage();

I get

Index 0 out of bounds for length 0

I am unable to understand the order of evaluation.

Java Version 1.8.0_341-b10 (64 bit)

Answer 1

The operator, + has higher precedence than the operator, ==

Therefore

return "Unexpected Error: " + e.getMessage() == null ? "No further details!" : e.getMessage()

is evaluated as follows:

if ("Unexpected Error: " + e.getMessage() == null)
    return "No further details!";
else
    return e.getMessage();

whereas

return "Unexpected Error: " + (e.getMessage() == null ? "No further details!" : e.getMessage());

is evaluated as

if (e.getMessage() == null)
    return "Unexpected Error: " + "No further details!";
else
    return "Unexpected Error: " + e.getMessage();

I hope it clears your doubt.