* added updated example codes
* updated example code StringToCharStream
* deleted StringToCharStream.java locally
* removed redundant file
* added code for apache commons collection SetUtils
* refactored example code
* added example code for bytebuddy
* added example code for PCollections
* update pom
* refactored tests for PCollections
* spring security xml config
* spring security xml config
* remove redundant comment
* example code for apache-shiro
* updated example code for Vavr Collections
* updated Vavr's Collection example
* updated Vavr Collection file
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