20. Another substring()

Answer:
Expression
Substring
Comment
String snake = "Rattlesnake";
"Rattlesnake"
Create original String
snake.substring(6)
"snake"
Characters starting at character 6 to the end
snake.substring(0)
"Rattlesnake"
The new substring contains all the characters of the original string
snake.substring(10)
"e"
Character 10 is the last one
snake.substring(11)
""
If beginIndex==length, an empty substring is created.
snake.substring(12)
 
If beginIndex is greater than length, a
IndexOutOfBoundsException is thrown.

Another substring()

substring(int beginIndex, int endIndex)

This method creates a new String containing characters from the original string starting at beginIndex and ending at endIndex-1.

Warning: the character at endIndex is not included.

The length of the resulting substring is endIndex-beginIndex.

Here is a picture that shows the character numbering. The 'n' is character 11.

Question 20:
What does this code write?
String stars = "*****" ;
int j = 1;
while ( j <= stars.length() )
{
  System.out.println( stars.substring(0,j) );
  j = j+1;
}