This is for Java

4. What is meant by "case sensitive"? Why is it important for a programmer to know that Java is a case-sensitive language? 6. What does a variable declaration tell the Java compiler about a variable? 8. What things must be considered when deciding on a data type to use for a variable? 10. What is the difference between comments that start with the // characters and com- ments that start with the /+ characters? 12. Assume that a program uses the named constant PI to represent the value 3.14. The program uses the named constant in several statements. What is the advantage of using the named constant instead of the actual value 3.14 in each statement