とりあえず後ろ5文字削除（≠５バイト）
public class TrimLast5String {

public static void main(String[] args) {
try {
BufferedReader br = new BufferedReader( new InputStreamReader( System.in ) );

while ( true ) {
TrimLast5String.trim( br.readLine() );
}
} catch (Exception e) {

}
}

public static void trim( String line ) {
int length = line.length();

if ( length > 5 ) {
System.out.println( line.substring( 0, length - 5 ) );
}
}
}