1Z0-811 What is Java Practice Question
A developer compiles a Java program successfully but gets 'ClassNotFoundException' when running it. What is the most likely cause?
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
✓
The classpath does not include the directory containing the .class file
ClassNotFoundException occurs when the JVM cannot find the class definition, typically due to the classpath not including the location of the .class file. Option A is wrong because Java version incompatibility leads to UnsupportedClassVersionError, not ClassNotFoundException. Option B is wrong because an incorrect main method signature causes NoSuchMethodError. Option C is wrong because having multiple classes does not cause ClassNotFoundException unless one of them is missing from the classpath.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The Java version is incompatible
Why it's wrong here
Version incompatibility leads to 'Unsupported major.minor version' error.
- ✗
The main method signature is incorrect
Why it's wrong here
Incorrect main signature yields 'Main method not found' error.
- ✗
The program has multiple classes
Why it's wrong here
Multiple classes do not cause ClassNotFoundException as long as they are accessible.
- ✓
The classpath does not include the directory containing the .class file
Why this is correct
ClassNotFoundException is thrown when the classpath does not contain the class.
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