public MutableString(final char[] a,final int offset,final int len){
  makeCompactMutableString(len);
  System.arraycopy(a,offset,array,0,len);
}

public MutableString ( final char [ ] a , final int offset , final int len ) { makeCompactMutableString ( len ) ; System . arraycopy ( a , offset , array , 0 , len ) ; }
creates a new compact mutable string copying a part of a given character array .
