first, the new project in MyEclipse will generally have the following four kinds of libraries:
JRE System Library, Java EE 6 Libraries, referenced libraries,web App Libraries
second, various libraries meanings
JRE System Library:Refers to the Java SE Common library file collection, the establishment of common Java projects will be used;
Java EE 6 Libraries:Refers to a collection of common library files for Java EE, and the creation of Web projects uses a collection of library files for this library collection and Java SE;
referenced Libraries: Refers to a collection of third-party library files that you use in your project. If you add the other jar packages that you need for your project directly to the project---Properties->java Build Path, Libraries, MyEclipse These jar packages are automatically categorized into a collection and named referenced Libraries, which is displayed in the project.
Q: do I often see jar package conflicts in SSH referenced Libraries jar file conflicts or Webroot/web-inf/lib jar file conflicts???
solution : The compile-time conflict is caused by a jar-package conflict in referenced libraries, and the runtime conflict is caused by a jar file conflict under Webroot/web-inf/lib. first referenced libraries can be a jar package that references webroot/web-inf/lib, or it can be a third-party jar package copied from somewhere else. Referenced libraries is a jar package used in a compiled environment, the so-called jar package used in a compiled environment is that when you write source files in Eclipse, the classes you need to refer to are from referenced Libraries in the jar in this collection; The jar package in Webroot/web-inf/lib is the jar package used in the runtime environment, and the jar package used in the so-called runtime environment is the set of jar packages that you need to use when you run your project, and note the distinction between the two environments: the compilation environment and the running environment.
Web App Libraries:This container dynamically manages CLASSPATH entries for types in the web-inf/lib and web-inf/classes di Rectories. Believe that a bit of English-based people can read.
about Web projects do not see the Web App Libraries, You can right-click the project/built path/configure built path/clicking on the Libraries tab to select the Add Library button on the right, in the popup window Select Web App Libraries Add
The meanings of various libraries in MyEclipse