How to get Java to wait for user Input -

i trying make irc bot channel. bot able take commands console. in attempt make main loop wait user input added loop:

while(!userinput.hasnext()); 

this did not seem work. have heard of bufferedreader have never used , not sure if able solve problem.

while(true) {         system.out.println("ready new command sir.");         scanner userinput = new scanner(system.in);          while(!userinput.hasnext());          string input = "";         if (userinput.hasnext()) input = userinput.nextline();          system.out.println("input '" + input + "'");          if (!input.equals("")) {             //main code         }         userinput.close();         thread.sleep(1000);     } 

there no need check available input waiting , sleeping until there since scanner.nextline() block until line available.

have @ example wrote demonstrate it:

public class scannertest {      public static void main(string[] args) {         scanner scanner = new scanner(system.in);         try {             while (true) {                 system.out.println("please input line");                 long = system.currenttimemillis();                 string line = scanner.nextline();                 long = system.currenttimemillis();                 system.out.printf("waited %.3fs user input%n", (now - then) / 1000d);                 system.out.printf("user input was: %s%n", line);             }         } catch(illegalstateexception | nosuchelementexception e) {             // system.in has been closed             system.out.println("system.in closed; exiting");         }     } } 

please input line
hello
waited 1.892s user input
user input was: hello
please input line
^d
system.in closed; exiting

so have use scanner.nextline() , app wait until user has entered newline. don't want define scanner inside loop , close since you're going use again in next iteration:

scanner userinput = new scanner(system.in); while(true) {         system.out.println("ready new command sir.");          string input = userinput.nextline();         system.out.println("input '" + input + "'");          if (!input.isempty()) {             // handle input         }     } }