That action adds the JAR to the build path.

该操作将 JAR 添加到构建路径。

Add the new JAR file to the build path manually.

手动地向构建路径添加新的 JAR 文件。

Clicking Open adds the jar file to the build path.

单击 Open，将此 jar 文件添加到构建路径中。

How can I add dependencies to project build path dynamically by the coding?

我怎么能动态依赖关系添加到项目的构建路径的编码吗?。

As already mentioned, since you added the JAR files to the WEB-INF\lib folder, then they are now on the build path.

我们已经提到过，因为您已经将JAR文件添加到WEB-INF\lib文件夹，所以它们现在就已经在构建路径上了。