How do you use sub string in java?

Answer 1

Substring method creates smaller string form bigger string , every time a new string is created but original character array buffer is used. so even if original string is 1G in size and substring is just 1K memory held by substring is 1G because of backed array. this can cause memory leak and prevent original string from garbage collection even if there is no direct reference.

Answer 2

Every Java function was programmed by someone who had the same problem as you. I recommend that you run a loop. Take an empty string, then using the String.charAt() method, add characters to the empty string until there is a complete substring.

public String mySubString(String original, int startIndex, int endIndex) {

String s = "";

for (int i = startIndex; i <= endIndex; i++) {

s += original.charAt(i);

}

return s;

}

Answer 3

The substring() method is used to return a part (or substring) of the String used to invoke the method. The first argument represents the starting location (zero-based) of the substring. If the call has only one argument, the substring returned will include the characters to the end of the original String. If the call has two arguments, the substring returned will end with the character located in the nth position of the original String where n is the second argument. Unfortunately, the ending argument is not zero-based, so if the second argument is 7, the last character in the returned String will be in the original String's 7 position, which is index 6. Let's look at an example:

String x = "0123456789";

System.out.println( x.substring(5) ); // output is "56789"

System.out.println( x.substring(5, 8)); // output is "567"

The first example should be easy: start at index 5 and return the rest of the String. The second example should be read as follows: start at index 5 and return the characters up to and including the 8th position (index 7).