public DocumentManifest addContent(DocumentManifestContentComponent t) { //3
      if (t == null)
        return this;
      if (this.content == null)
        this.content = new ArrayList<DocumentManifestContentComponent>();
      this.content.add(t);
      return this;
    }
public DocumentManifest addContent ( DocumentManifestContentComponent t ) { if ( t == null ) return this ; if ( this . content == null ) this . content = new ArrayList < DocumentManifestContentComponent > ( ) ; this . content . add ( t ) ; return this ; }
syntactic sugar