The difference of various libraries in MyEclipse

(from the flies are also meat blog, thank you)

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 running your project; Note the distinction between 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 difference of various libraries in MyEclipse