Which of these are keywords in Java？（）  

Which statements， when inserted at the indicated positi...

单项选择题

Which statements， when inserted at the indicated position in the following code， will cause a runtime exception when attempting to run the program？（）  
class A {}  
class B extends A {}  
class C extends A {}  
public class Q3ae4 {  
public static void main（String args[]） { 
 A x = new A（）； 
 B y = new B（）；  
C z = new C（）；  
// insert statement here  
}  
} 

WhichmethodsfromtheStringandStringBufferclassesmodifyth...

单项选择题Which methods from the String and StringBuffer classes modify the object on which they are called？（）  

Which is the earliest line in the following code after ...

单项选择题

Which is the earliest line in the following code after which the object created on the line marked （0） will be a candidate for being garbage collected， assuming no compiler optimizations are done？ （） 
public class Q76a9 {  
static String f（） {  
String a = "hello"；  
String b = "bye"； // （0） 
 String c = b + "!"； // （1）  
String d = b；  b = a； // （2）  
d = a； // （3）  
return c； // （4）  }  
public static void main（String args[]） { 
 String msg = f（）；  
System.out.println（msg）； // （5） 
 }  
}