This 1Z0-811 practice question tests your understanding of exception handling and development tools. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
What does the java command with -jar option do?
Compiles Java files inside the JAR
Why wrong: compilation is done by javac.
Executes a JAR file by reading its manifest
java -jar runs the JAR with the class from manifest.
Lists contents of the JAR file
Why wrong: listing is done with jar tf.
Creates a new JAR file
Why wrong: Creating JAR files is done with jar command.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Executes a JAR file by reading its manifest
The `java -jar` command executes a JAR file by reading the `Main-Class` entry from the JAR's manifest file (`META-INF/MANIFEST.MF`). This tells the Java launcher which class contains the `public static void main(String[] args)` method to start the application. It does not compile, list, or create JAR files.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Compiles Java files inside the JAR
Why it's wrong here
compilation is done by javac.
Executes a JAR file by reading its manifest
Why this is correct
java -jar runs the JAR with the class from manifest.
Related concept
Read the scenario before looking for a memorised answer.
Lists contents of the JAR file
Why it's wrong here
listing is done with jar tf.
Creates a new JAR file
Why it's wrong here
Creating JAR files is done with jar command.
Common exam traps
Oracle often tests the misconception that `java -jar` compiles or manipulates the JAR file, when in fact it strictly executes the application defined in the manifest.
Trap categories for this question
Command / output trap
Creating JAR files is done with jar command.
Detailed technical explanation
Under the hood, the `java -jar` command invokes the `sun.misc.Launcher` (or `jdk.internal.loader.ClassLoader` in modern JDKs) to load the JAR and its dependencies. The manifest's `Main-Class` attribute must be fully qualified (e.g., `com.example.Main`), and if the JAR has a `Class-Path` entry, the launcher will also load those referenced JARs. A real-world scenario is packaging a Spring Boot application into a fat JAR where the manifest points to `org.springframework.boot.loader.JarLauncher`.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the 1Z0-811 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
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FAQ
Exception Handling and Development Tools — This question tests Exception Handling and Development Tools — Read the scenario before looking for a memorised answer..
The correct answer is: Executes a JAR file by reading its manifest — The `java -jar` command executes a JAR file by reading the `Main-Class` entry from the JAR's manifest file (`META-INF/MANIFEST.MF`). This tells the Java launcher which class contains the `public static void main(String[] args)` method to start the application. It does not compile, list, or create JAR files.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This 1Z0-811 practice question is part of Courseiva's free Oracle certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 1Z0-811 exam.
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