How to Fix 'Error: Selection does not contain a main type' in Eclipse?-javaTutorial-php.cn

Home

Java

javaTutorial

How to Fix 'Error: Selection does not contain a main type' in Eclipse?

Patricia Arquette

Nov 16, 2024 am 11:25 AM

How to Fix

Troubleshooting "Error: Selection does not contain a main type" in Eclipse

When attempting to run Java files within a fresh project, users may encounter the error "Selection does not contain a main type." This issue arises when the folder containing the main Java class is not designated as a source folder within Eclipse. To rectify this issue and successfully execute the main file, follow the steps outlined below:

Locate the folder containing the main Java class with the main method.
Right-click on the folder and navigate to Build Path.
Select Use as Source Folder to designate the folder as a source directory.

After completing these steps, the option to run the main file as a Java application should become available. To execute the main file, right-click on the class file and select Run as Java Application.

The above is the detailed content of How to Fix 'Error: Selection does not contain a main type' in Eclipse?. For more information, please follow other related articles on the PHP Chinese website!

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

How does platform independence benefit enterprise-level Java applications?May 03, 2025 am 12:23 AM

Java is widely used in enterprise-level applications because of its platform independence. 1) Platform independence is implemented through Java virtual machine (JVM), so that the code can run on any platform that supports Java. 2) It simplifies cross-platform deployment and development processes, providing greater flexibility and scalability. 3) However, it is necessary to pay attention to performance differences and third-party library compatibility and adopt best practices such as using pure Java code and cross-platform testing.

What role does Java play in the development of IoT (Internet of Things) devices, considering platform independence?May 03, 2025 am 12:22 AM

JavaplaysasignificantroleinIoTduetoitsplatformindependence.1)Itallowscodetobewrittenonceandrunonvariousdevices.2)Java'secosystemprovidesusefullibrariesforIoT.3)ItssecurityfeaturesenhanceIoTsystemsafety.However,developersmustaddressmemoryandstartuptim

Describe a scenario where you encountered a platform-specific issue in Java and how you resolved it.May 03, 2025 am 12:21 AM

ThesolutiontohandlefilepathsacrossWindowsandLinuxinJavaistousePaths.get()fromthejava.nio.filepackage.1)UsePaths.get()withSystem.getProperty("user.dir")andtherelativepathtoconstructthefilepath.2)ConverttheresultingPathobjecttoaFileobjectifne

What are the benefits of Java's platform independence for developers?May 03, 2025 am 12:15 AM

Java'splatformindependenceissignificantbecauseitallowsdeveloperstowritecodeonceandrunitonanyplatformwithaJVM.This"writeonce,runanywhere"(WORA)approachoffers:1)Cross-platformcompatibility,enablingdeploymentacrossdifferentOSwithoutissues;2)Re

What are the advantages of using Java for web applications that need to run on different servers?May 03, 2025 am 12:13 AM

Java is suitable for developing cross-server web applications. 1) Java's "write once, run everywhere" philosophy makes its code run on any platform that supports JVM. 2) Java has a rich ecosystem, including tools such as Spring and Hibernate, to simplify the development process. 3) Java performs excellently in performance and security, providing efficient memory management and strong security guarantees.

How does the JVM contribute to Java's 'write once, run anywhere' (WORA) capability?May 02, 2025 am 12:25 AM

JVM implements the WORA features of Java through bytecode interpretation, platform-independent APIs and dynamic class loading: 1. Bytecode is interpreted as machine code to ensure cross-platform operation; 2. Standard API abstract operating system differences; 3. Classes are loaded dynamically at runtime to ensure consistency.

How do newer versions of Java address platform-specific issues?May 02, 2025 am 12:18 AM

The latest version of Java effectively solves platform-specific problems through JVM optimization, standard library improvements and third-party library support. 1) JVM optimization, such as Java11's ZGC improves garbage collection performance. 2) Standard library improvements, such as Java9's module system reducing platform-related problems. 3) Third-party libraries provide platform-optimized versions, such as OpenCV.

Explain the process of bytecode verification performed by the JVM.May 02, 2025 am 12:18 AM

The JVM's bytecode verification process includes four key steps: 1) Check whether the class file format complies with the specifications, 2) Verify the validity and correctness of the bytecode instructions, 3) Perform data flow analysis to ensure type safety, and 4) Balancing the thoroughness and performance of verification. Through these steps, the JVM ensures that only secure, correct bytecode is executed, thereby protecting the integrity and security of the program.

See all articles