Java base type

String:

Public final class String    implements Java.io.Serializable, Comparable<string>, charsequence {    /** the Value is used for character storage. */    Private final char value[];    /** Cache The hash code for the string */    private int hash;//Default to 0    /** with serialversionuid from JDK 1.0. 2 for Interoperability */    private static final long serialversionuid = -6849794470754667710l;    ...   }

StringBuffer:

Public final class StringBuffer    extends Abstractstringbuilder    implements Java.io.Serializable, charsequence{    @Override public    synchronized stringbuffer append (Object obj) {        tostringcache = null;        Super.append (string.valueof (obj));        return this;    }}

StringBuilder:

Public final class StringBuilder    extends Abstractstringbuilder    implements Java.io.Serializable, charsequence{@Override public    StringBuilder append (Object obj) {      return append (string.valueof (obj));}   }

Java base type