code: public List<UnifiedDiffBlock<String, Character>> unified(String previous, String next)
      {
          setError(null);
  
          try {
              DiffResult<String> diffResult =
                  this.diffManager.diff(this.lineSplitter.split(previous), this.lineSplitter.split(next), null);
              UnifiedDiffConfiguration<String, Character> config = this.unifiedDiffDisplayer.getDefaultConfiguration();
              config.setSplitter(this.charSplitter);
              return this.unifiedDiffDisplayer.display(diffResult, config);
          } catch (DiffException e) {
              setError(e);
              return null;
          }
      }
docs: Builds an unified diff between two versions of a text. The unified diff provides information about both
  line-level and character-level changes (the later only when a line is modified).
  
  @param previous the previous version
  @param next the next version
  @return the list of extended diff blocks