单项选择题
A. System.gc();
B. Runtime.gc();
C. System.freeMemory();
D. Runtime.getRuntime().growHeap();
E. Runtime.getRuntime().freeMemory();
单项选择题 11. public void genNumbers() { 12. ArrayList numbers = new ArrayList(); 13. for (int i=0; i<10; i++) { 14. int value = i * ((int) Math.random()); 15. Integer intObj = new Integer(value); 16. numbers.add(intObj); 17. } 18. System.out.println(numbers); 19. } Which line of code marks the earliest point that an object referenced by intObj becomes a candidate for garbage collection?()
单项选择题 class Foo { private int x; publicFoo(intx) {this.x=x; } public void setX( int x) { this.x = x; } public int getX() { return x; } } public class Gamma { static Foo fooBar( Foo foo) { foo = new Foo( 100); return foo; } public static void main( String[] args) { Foo foo = new Foo( 300); System.out.print( foo.getX() + “-“); Foo fooFoo = fooBar( foo); System.out.print( foo.getX() + “-“); System.out.print( fooFoo.getX() + “-“); foo = fooBar( fooFoo); System.out.print( foo.getX() + “-“); System.out.prmt( fooFoo.getX()); } } What is the output of this program?()
多项选择题 10. class Inner { 11. private int x; 12. public void setX( int x) { this.x = x; } 13. public int getX() { return x; } 14. } 15. 16. class Outer { 17. private Inner y; 18. public void setY( Inner y) { this.y = y; } 19. public Inner getY() { return y; } 20. } 21. 22. public class Gamma { 23. public static void main( String[] args) { 24. Outer o = new Outer(); 25. Inner i = new Inner(); 26.int n=10; 27. i.setX(n); 28. o.setY(i); 29. // insert code here 30. System.out.println( o.getY().getX()); 31. } 32. } Which three code fragments, added individually at line 29, produce the output 100?()