how to remove part of string in java code example

Example 1: delete ending part of the string java

//To delete starting from "opened"
String str ="13 opened by someone";

String result = str.substring(0,str.lastIndexOf(" opened"));

Example 2: remove a string from a string java

str = "manchester united (with nice players)"
matched = str.match(/.*(?=\()/)
str.replace(matched[0].strip) if matched