1Z0-811 Primitives, Strings and Operators Practice Question
Which of the following is a valid Java identifier?
⚠ Common exam trap
Oracle often tests the rule that identifiers cannot start with a digit, but the trap here is that candidates may mistakenly think underscores are invalid or that keywords like 'class' can be used as identifiers if they forget Java's reserved word list.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
_myVar
(_myVar) is a valid Java identifier because it starts with an underscore, which is permitted by the Java Language Specification. Java identifiers must begin with a letter (A-Z, a-z), dollar sign ($), or underscore (_), and cannot start with a digit or contain hyphens. The underscore is explicitly allowed, making _myVar a legal identifier.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
2variable
Why it's wrong here
Cannot start with digit.
- ✗
class
Why it's wrong here
Reserved keyword.
- ✓
_myVar
Why this is correct
Underscore allowed.
- ✗
my-var
Why it's wrong here
Hyphen not allowed.
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