Given a string of digits, remove leading zeros from it.

Examples:

Input : 00000123569
Output : 123569

Input : 000012356090
Output : 12356090

We use the StringBuffer class as Strings are permanent.

1) Count leading zeros.
2) Use StringBuffer replace function to remove characters equal to above count.

// Java program to remove leading/preceding zeros
// from a given string
import java.util.Arrays;
import java.util.List;

/* Name of the class to remove leading/preceding zeros */
class RemoveZero
{
	public static String removeZero(String str)
	{
		// Count leading zeros
		int i = 0;
		while (i < str.length() && str.charAt(i) == '0')
			i++;

		// Convert str into StringBuffer as Strings
		// are immutable.
		StringBuffer sb = new StringBuffer(str);

		// The StringBuffer replace function removes
		// i characters from given index (0 here)
		sb.replace(0, i, "");

		return sb.toString(); // return in String
	}

	// Driver code
	public static void main (String[] args)
	{
		String str = "00000123569";
		str = removeZero(str);
		System.out.println(str);
	}
}

Output:

123569