1,To check if a string s contains the suffix "Java", you may write ________.

if (s.endsWith("Java")) ...

if (s.lastIndexOf("Java") >= 0) ...

if (s.substring(s.length() - 4).equals("Java")) ...

if (s.substring(s.length() - 5).equals("Java")) ...

if (s.charAt(s.length() - 4) == 'J' && s.charAt(s.length() - 3) == 'a' && s.charAt(s.length() - 2) == 'v' && s.charAt(s.length() - 1) == 'a') ...

2, Suppose s1 and s2 are two strings. Which of the following statements or expressions is incorrect?

String s3 = s1 - s2;

boolean b = s1.compareTo(s2);

char c = s1[0];

char c = s1.charAt(s1.length());

3, The ________ method parses a string s to a double value.

double.parseDouble(s);

Double.parsedouble(s);

double.parse(s);

Double.parseDouble(s);