In the provided code snippet:
Boolean isOK;
Integer x;
String theString = 'Hello';
if (isOK == false && theString == 'Hello') {
x = 1;
} else if (isOK == true && theString == 'Hello') {
x = 2;
} else if (isOK != null && theString == 'Hello') {
x = 3;
} else {
x = 4;
}
Variable Initialization:
Boolean isOK; → Declared but not initialized, so isOK is null.
Integer x; → Declared but not initialized.
String theString = 'Hello'; → Initialized to 'Hello'.
Evaluation of Conditions:
First Condition:
if (isOK == false && theString == 'Hello')
isOK == false → Since isOK is null, this evaluates to false.
Overall condition: false && true → false.
Second Condition:
else if (isOK == true && theString == 'Hello')
isOK == true → Since isOK is null, this evaluates to false.
Overall condition: false && true → false.
Third Condition:
else if (isOK != null && theString == 'Hello')
isOK != null → Since isOK is null, this evaluates to false.
Overall condition: false && true → false.
Else Block:
else {
x = 4;
}
Since none of the previous conditions are met, the else block is executed.
x is assigned the value 4.
Conclusion:
The variable x is assigned the value 4.
Reference:
Variable Initialization:
"Instance variables are initialized to null. Local variables are not initialized, so their value is undefined until you assign a value."
- Apex Developer Guide: Variables
Conditional Statements and Null Values:
"In Apex, comparisons with null are straightforward. If you compare null to a value, the result is false."
- Apex Developer Guide: Expressions