非常不错的SCJP真题回忆

PART 1
Boolean a=new Boolean; 
System.out.println(a[I]); } 
Compilation Error in Line 2 
Exception in Line 4 
Will print false 
Ans:F 
Integer b= new Integer(10); 
System.out.println(b.intvalue()); 
void Add(Integer b) 
int I= b.intvalue(); 
b= new Integer(I) 
What will be printed out? 
Will print 10 
String is not possible 
class 
Ans:b 
public static void main(String args) 
String a =args[1]; 
String c =args; 
} 
the 'c' ? 
dog 
Compilation Error 
Ans:E 
{ 
Float c; 
float fl=4.2f; 
} 
f.equls(d) 
c==d 
Ans:B,D 
{ 
System.out.println("s = "+s); 
what will be printed out? 
An Exception will occur 
Will print s= 
6. class s extends Thread{int j=0; 
try{Thread.sleep(5000);} 
j=100; 
public static void main(String args) 
s t1=new s(); 
System.out.println(t1.j); 
} 
you have make t1 as Daemon Thread 
You have to suspend the main when the thread starts and resume it after 
You have to interrupt the main thread 
7. What will happen if you compile/run this code? 
2: { 
4: { 
6: 
8: } 
10: public static void main(String args) 
12: Q1 a = new Q1(); 
14: t.start();} 
||| 
B) Runtime exception at line 13. 
D) Prints "Before start of Thread " 
Ans:A 
int x=0,y=0; 
int addY(){y++; return y;} 
{ 
System.out.println(addX()+""+addY()); 
public static void main(String args) 
s run=new s(); 
Thread t2=new Thread(run); 
t2.start(); 
} 
Will print in this order 11 22 33厖 
Will print in this order 12 3厖123厖 
Ans:C 
class s implements Runnable{ 
synchronized void addX(){x++; } 
void addXY(){x++;y++;} 
y)? true:false;) 
{ 
System.out.println(check()); } 
{ s run=new s(); 
Thread t2=new Thread(run); 
t2.start(); 
} 
Select all that apply 
call addY() and addX() simultaneously for number of times in run() 
Ans:B,C 
A. init(); 
C. run(); 
Ans:B 
executing? 
B. stop(); 
D. wait(); 
F. notifyAll() 
Ans:EF 
12. class Outer{ 
} 
Inner a= new Inner(); 
Outer o= new Outer();Outer.Inner a= new o.Inner(); 
Ans:CD 
A. Any variables in the enclosing scope 
C. Static variables declared in side the method 
Ans:D 
an Inner class can access all variables in the any enclosing scope 
an inner class can be declared as private 
an interface 
15. A ----- is a class that is a collection which cannot contain any 
SortedSet 
Sorted Map 
TreeSet 
16. What is true about Map select one 
A map will use unique key to store value 
Ans:C 
object, or null if the name has no parent part? 
getParentDir() 
parentDirectory() 
18. Which class should be used in situations that require writing 
LineNumberWriter 
PrintStream 
Ans:B 
new RandomAccessFile(f,"rw").writeByte(?; 
DataInputStream d=new DatainputStream(fis); 
FilterInputStream fis=new FilterInputStream(f,true); 
d.writeBytes(? 
DataOutputStream d=new DataOutputStream(fis);