Scanner input accepting Strings skipping every other input inside a while loop. [duplicate]

Answer 1

You loop is doing exactly what you've told it to...

• Read a line of text and add it to set1
• Read a line of text and check to see if it equals "EXIT"
• Repeat as required...

So, every second request is being used to check for the exit state. Instead, you should assign the text from the input to a variable and use it to do you checks, for example...

do {
    String text = input.nextLine();
    if (!"EXIT".equals(text)) {
        set1.add();
    }
} while (!"EXIT".equals(text));

ps- Yes, I know, you could use break ;)

Answer 2

The reason is, you're calling input.nextLine() twice:

do {

    set1.add(input.nextLine());

}
while (!"EXIT".equals(input.nextLine()));

A much easier way than do-while is while:

while (!(String in = input.nextLine()).equals("EXIT")) {
    set1.add(in);
}

Answer 3

You ask for input twice

do {

    set1.add(input.nextLine()); // you enter a number

}
while (!"EXIT".equals(input.nextLine())); // what if you enter another number? 
// it'll just loop again, skipping that number

You need to ask for input once and use that either to stop or add it to your set.