Shulou(Shulou.com)06/03 Report--

[IGT] Paper Test For Campus Recruiting

Note: share out, only do personal knowledge points to fill gaps and urge yourself to study harder! The answer given by the bold scarlet letter may be wrong, and I hope someone will point it out.)

Part 1:

1 、 which of these is a legal definition of a method named m assuming it throws IOExecption,and returns void .Also assume that the method does not take any arguments.Select the one correct answer.

A void m () throws IOExecption {}

B void m () throw IOExecption {}

C void m (void) throw IOExecption {}

D void m () {} throws IOExecption {}

2 、 which of the following is legal identifier name in java.

A% abcd

B 1abcd (the first is the number 1)

C package

D _ a_long_name

(knowledge point description: the Java language stipulates that identifiers begin with letters, underscores "_" or the dollar sign "$", followed by a sequence of numbers, letters, underscores or dollar signs, of course, not with keywords. )

3 、 what will happen when you attempt to compile and run the following code?

Package igt

Public class igt {

Public static void main (String [] args) {

Int i

Switch (I) {

Case 0:System.out.println (0)

Case 1:System.out.println (1); break

Case 2:System.out.println (2)

Case 3:System.out.println (3); break

}

}

}

A 0

B 01

C 0123

D compile error

(knowledge note: on the question of whether java variables are initialized automatically-member variables are initialized, local variables are not initialized. If a local variable is not initialized when it is defined, the system will not initialize it automatically, so there will be errors at compile time. As shown in the following figure:

4 、 what will be the output of the program?

Public class test_4 {

Static class A {

Public int x = 10

Public int y = 20

Int f () {

Return y

}

}

Static class B extends A {

Public int x = 1

Public int y = 30

Int f () {

Return y

}

}

Public static void main (String [] args) {

An a = new B ()

System.out.print (a.x+ ",")

System.out.println (a.f ())

}

}

A 10,20

B 10,30

C 1,20

D 1,30

The result of the experiment is B, which is puzzling.

5 、 what will be the output of the program?

Public class test_5 extends Base {

Static {

System.out.print ("6")

} {

System.out.print ("5")

}

Public test_5 () {

System.out.print ("4")

}

Public static void main (String [] args) {

New test_5 ()

}

}

Class Base {

Static {

System.out.print ("3")

} {

System.out.print ("2")

}

Public Base () {

System.out.print ("1")

}

}

A 326514

B 361425

C 362154

D 362514

The result of the experiment is C, which is puzzling.

Part 2:

6 、 please decribe the scenarios of using String StringBuffer StringBuilder,and what is the difference between StringBuffer and StringBuilder?

7 、 please explain the difference between checked exception and runtime exception and the usage of these two kinds of exception.

8. Please give an example of self-defined class that could be sorted in Collections.sort () method

9 、 please list at least three design patterns and its usage in your daily development.

Part 3:

10 、 please implement a function to find the longest common sub-string of two given string.

For example:

String a: abcdefg12345

String b:cdef234

Longest common sub-string:cdef

String matching problems are often examined and need to be studied thoroughly! )

Unsolved problem, to be continued.

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