The org.apache.lucene.analysis.standard package contains three fast grammar-based tokenizers constructed with JFlex:

• StandardTokenizer: as of Lucene 3.1, implements the Word Break rules from the Unicode Text Segmentation algorithm, as specified in Unicode Standard Annex #29. Unlike UAX29URLEmailTokenizer, URLs and email addresses are not tokenized as single tokens, but are instead split up into tokens according to the UAX#29 word break rules.
  StandardAnalyzer includes StandardTokenizer, StandardFilter, LowerCaseFilter and StopFilter. When the Version specified in the constructor is lower than 3.1, the ClassicTokenizer implementation is invoked.
• ClassicTokenizer: this class was formerly (prior to Lucene 3.1) named StandardTokenizer. (Its tokenization rules are not based on the Unicode Text Segmentation algorithm.) ClassicAnalyzer includes ClassicTokenizer, StandardFilter, LowerCaseFilter and StopFilter.
• UAX29URLEmailTokenizer: implements the Word Break rules from the Unicode Text Segmentation algorithm, as specified in Unicode Standard Annex #29. URLs and email addresses are also tokenized according to the relevant RFCs.