Tag: programming languages

Given: class CardBoard { Short story = 5; CardBoard go(CardBoard cb) { cb = null; return cb; } public static void main(String[] args) { CardBoard c1 = new CardBoard(); CardBoard c2 = new CardBoard(); CardBoard c3 = c1.go(c2); c1 = null; // do Stuff } } When // doStuff is reached, how many objects are eligible for GC?

Given: class Alien { String invade(short ships) { return "a few"; } String invade(short... ships) { return "many"; } } class Defender { public static void main(String [] args) { System.out.println(new Alien().invade(7)); } } What is the result?

Given: 1. class Dims { 2. public static void main(String[] args) { 3. int[] [] a = {{1,2,}, {3,4}}; 4. int[] b = (int []) a [1] ; 5. Object o1 = a; 6. int[] [] a2 = (int[] []) o1; 7. int[] b2 = (int []) o1; 8. System.out.println(b[1]); 9. } } What is the result?

Given: class Eggs { int doX(Long x, Long y) { return 1; } int doX(long... x) { return 2; } int doX(Integer x, Integer y) { return 3; } int doX(Number n, Number m) { return 4; } public static void main(String[] args) { new Eggs().go(); } void go () { short s = 7; System.out.print(doX(s,s) + " "); System.out.println(doX(7,7)); } }

Which is true? (Choose all that apply.)

Given: 1. class Convert { 2. public static void main(String[] args) { 3. Long xL = new Long(456L); 4. long x1 = Long.valueOf("123"); 5. Long x2 = Long.valueOf("123"); 6. long x3 = xL.longValue(); 7. Long x4 = xL.longValue(); 8. Long x5 = Long.parseLong("456"); 9. long x6 = Long.parseLong("123"); 10. } 11. } Which will compile using Java 5, but will NOT compile using Java 1.4? (Choose all that apply.)

Given: 1. class Bigger { 2. public static void main(String[] args) { 3. // insert code here 4. } 5. } 6. class Better { 7. enum Faster {Higher, Longer}; 8. } Which, inserted independently at line 3, will compile? (Choose all that apply.)

Given: 1. class Example { 2. public static void main(String[] args) { 3. Short s = 15; 4. Boolean b; 5. // insert code here 6. } 7. } Which, inserted independently at line 5, will compile? (Choose all that apply.)

Given two files: 1. class One { 2. public static void main(String[] args) { 3. int assert = 0; 4. } 5. } 1. class Two { 2. public static void main(String[] args) { 3. assert(false); 4. } 5. } And the four command-line invocations: javac -source 1.3 One.java javac -source 1.4 One.java javac -source 1.3 Two.java javac -source 1.4 Two.java What is the result? (Choose all that apply.)

Given: class Mixer { Mixer() { } Mixer(Mixer m) { ml = m;} Mixer m1; public static void main(String[] args) { Mixer m2 = new Mixer(); Mixer m3 = new Mixer(m2); m3.go(); Mixer m4 = m3.m1; m4.go(); Mixer m5 = m2.m1; m5.go(); } void go() { System.out.print("hi "); } } What is the result?