Adding the actual quote characters is only a tiny fraction of the problem; once you have done that, you are likely to face the real problem: what happens if the string already contains quotes, or line feeds, or other unprintable characters?
The following method will take care of everything:
public static String escapeForJava( String value, boolean quote )
{
StringBuilder builder = new StringBuilder();
if( quote )
builder.append( "\"" );
for( char c : value.toCharArray() )
{
if( c == '\'' )
builder.append( "\\'" );
else if ( c == '\"' )
builder.append( "\\\"" );
else if( c == '\r' )
builder.append( "\\r" );
else if( c == '\n' )
builder.append( "\\n" );
else if( c == '\t' )
builder.append( "\\t" );
else if( c < 32 || c >= 127 )
builder.append( String.format( "\\u%04x", (int)c ) );
else
builder.append( c );
}
if( quote )
builder.append( "\"" );
return builder.toString();
}