System.gc();
Runtime.gc();
System.freeMemory();
Runtime.getRuntime().growHeap();
Runtime.getRuntime().freeMemory();
第1题:
class One { void foo() {} } class Two extends One { //insert method here } Which three methods, inserted individually at line 14, will correctly complete class Two?()
第2题:
10. class Line { 11. public static class Point { } 12. } 13. 14. class Triangle { 15. // insert code here 16. } Which code, inserted at line 15, creates an instance of the Point class defined in Line?()
第3题:
11.rbo = new ReallyBigObject();12.//more code here13.rbo = null;14./*insert code here*/Which statement should be placed at line 14 to suggest that the virtual machine expend effort toward recycling the memory used by the objectrbo?()
A.System.gc();
B.Runtime.gc();
C.System.freeMemory();
D.Runtime.getRuntime().growHeap();
E.Runtime.getRuntime().freeMemory();
第4题:
11. public interface Status { 12. /* insert code here */ int MY_VALUE = 10; 13. } Which three are valid on line 12?()
第5题:
11. public class Counter { 12. public static void main(String[] args) { 13. int numArgs = /* insert code here */; 14. } 15. } and the command line: java Counter one fred 42 Which code, inserted at line 13, captures the number of arguments passed into the program?()
第6题:
11. List list = // more code here 12. Collections.sort(list, new MyComparator()); Which code will sort this list in the opposite order of the sort in line 12?()
第7题:
现有: 1. class Propeller2 { 2. pulolic static void main (String[]args)//add code here? 3. { new Propeller2().topGo(); } 4. 5.void topGo() //add code here? 6. { middleGo(); } 7. 8.void middleGo() //add code here? 9. { go(); System.out.println ("late middle"); } void go() //add code here? 12. {throw new Exception(); } 13. } 为使代码通过编译,需要在哪一行加入声明throws Exception?()
第8题:
A.int foo() { /* more code here */ }
B.void foo() { /* more code here */ }
C.public void foo() { /* more code here */ }
D.private void foo() { /* more code here */ }
E.protected void foo() { /* more code here */ }
第9题:
12. Date date = new Date(); 13. df.setLocale(Locale.ITALY); 14. String s = df.format(date); The variable df is an object of type DateFormat that has been initialized in line 11. What is the result if this code is run on December 14, 2000?()
第10题:
10. interface Foo {} 11. class Alpha implements Foo {} 12. class Beta extends Alpha {} 13. class Delta extends Beta { 14. public static void main( String[] args) { 15. Beta x = new Beta(); 16. // insert code here 17. } 18. } Which code, inserted at line 16, will cause a java.lang.ClassCastException?()