北京联合大学师范学院java期末考试1选择

Object-Oriented Programming encapsulates:A. Data and methods.B. Information hiding.C. Classes.D. AdjectivesIf class A extends B, then:A. Class A is the base class.B. Class A is the superclass.C. Class A inherits from class B.D. Class B is the derived class.What will happen if you try to compile and run the following codepublic class MyClass{public static v oid main(String arguments[]){amethod(arguments);}public void amethod(String[] arguments){System.out.println(arguments);System.out.println(arguments[1]);}}A) error Can't make static reference to void amethod.B) error method main not correctC) error array must include parameterD) amethod must be declared with StringAn instance variable has which of the following scopes?A. Block scope.B. Method scope.C. Class scope.D. None of the above.Which of the following statements about arrays are true? (1). Arrays are a group of contiguous memory locations, where each location is an element.(2). Elements are located by subscript or index.(3). The length of array c is determined by the expressionc.length();(4). The seventh element of array c is specified by c[7].A. (1), (3), (4)B. (1), (2)C. (3), (4)D. (1), (2), (3), (4).A package is:A. A directory structure used to organize classes and interfaces.B. A mechanism for software reuse.C. A group of related classes and interfaces.D. All of the above.Constructors:A. Have the same name as the class.B. May not specify a return type.C. Are called automatically when an object is instantiated.D. All of the above.An instance variable is hidden in the scope of a method whenA. The instance variable has the same name as the method.B. The instance variable has the same name as a local variable in the method.C. The instance variable has the same name as the class.D. The instance variable has the same name as the file..Read the following program:public class Test{public static void main(String[] args){String foo = args [1];System.out.println(args [1]+80);}}And command line invocation:Java Test 1 8 9What is the result?A. 880B. The program throws an exception.C. 88D. The code does not compile.Which of the following will be used to create an instances of a class if the programmer does not define a constructor?A. A default constructor.B. An overloaded constructor.C. The Object class constructor with the name of the desired class passed in as an argument.D. If no constructor is written, then one is not needed.When overriding the method paintComponent( Graphics g ) A. The statement super.paintComponent(g) must be the last statement in the overriding method.B. The statement super.paintComponent(g) must be the first statement in the overriding method.C. The statement super.paintComponent(g) must occur after any customized drawing statements.D. The statement super.paintComponent(g) must not be used.Advantages of using interfaces include which of the following: a. Flexibility in implement ation and in accommodating later functionality.b. Providing standard values for many different classes to use.c. Increasing opportunities to use polymorphism多态.d. Creating a bank of methods for which the code is hidden so that the classes whic h implement the interfaces don’t have to define them.A.All of the above.B.None of the above.C.a, c and d.D.a, b and c.Which of the following is not a valid Java identifier标识符?aa.my Valueb.$_AAA1c.widthd.m_xWhich of the following cannot cause a syntax error to be reported by the Javacompiler? da.Mismatched {}b.Missing */ in a commentc.Missing ;d.Extra blank lines.Which command compiles the Java source code file Welcome.java? ba.cd Welcome.javab.javac Welcome.javac.java Welcome.javapile Welcome.javaWhich command executes the Java class file Welcome.class?ca.javac Welcome.classb.java Welcome.classc.java Welcomed.run Welcome.classWhich of the following statement displays Hello World? ba.System.out.printf( “%2s”, “Hello ” “World” );b.System.out.p rintf( “%s %s”, “Hello”, “World” );c.System.out.printf( “%s%s”, “Hello, World” );d.System.out.printf( “s% s%”, “Hello”, “World” );A(n) ________ enables a program to read data from the user.ca.printf.b.import declaration.c.Scanner.d.main.What is the value of result after the following Java statements execute? aint a, b, c, d, result;a = 4;b = 12;c = 37;d = 51;result = d % a * c + a % b + a;a.119b.51c.127d.59Which of the following statements about the break statement is false? ca.The break statement is used to exit a repetition structureearly and continue execution after the loop.b.A break statement can only break out of an immediatelyenclosing while, for, do…while or switch statement..c.The break statement, when executed in a while, for ordo…w hile, skips the remaining statements in the loopbody and proceeds with the next iteration of the loop.mon uses of the break statement are to escape earlyfrom a loop or to skip the remainder of a switch.Method headers contain all of the following except: ba. Access modifier.b. Left brace.c. Name of method.d. Return type.Every Java application is composed of at least one: ca.public methodb.data memberc.public class declarationd.imported classCalling a method of an object requires which item? aa. The dot separator.b. Open and close braces.c. The new keyword.d.None of the above.Which of the following statements about the continue statement is true? da.The continue statement is used to exit a repetition structureearly and continue execution after the loop.b.The continue statement is used to continue after a switchstatement.c.The continue statement does not alter the flow of control.d.A continue statement proceeds with the next iteration of theimmediately enclosing while, for, do…while statement. What is the default value of a reference? ca. 0.b. “”.c. null.d. default.What is output by the following Java code segment? d int temp;temp = 180;if ( temp > 90 ){System.out.println( "This porridge is too hot." );// cool downtemp = temp – ( temp > 150 ? 100 : 20 );} // end ifelse{if ( temp < 70 ){System.out.println("This porridge is too cold.");// warm uptemp = temp + (temp < 50 ? 30 : 20);} // end if} // end elseif ( temp == 80 )System.out.println( "This porridge is just right!" );a.This porridge is too hot.b.This porridge is too cold.This porridge is just right!c.This porridge is just right!d.None of the above.Suppose variable gender is MALE and age equals 60, how is the expression( gender == FEMALE ) && ( age >= 65 )evaluated? aa.The condition ( gender == FEMALE ) is evaluated firstand the evaluation stops immediately.b.The condition ( age >= 65 ) is evaluated first and theevaluation stops immediately.c.Both conditions are evaluated, from left to right.d.Both conditions are evaluated, from right to left.How many times is the body of the loop below executed? d int counter;counter = 1;while ( counter > 20 ){// body of loopcounter = counter + 1;} // end whilea.19.b.20.c.21.d.0.Which of the following terms is NOT used to refer to asentinel value that breaks out of a while loop? ba.signal value.b.break out value.c.dummy value.d.flag value.Which statement is false? ca.To ensure that the operands are of the same type, Javaperforms implicit conversion on selected operands.b.Cast operators are unary operators.c.Cast operators associate from right to left and are one levellower than the multiplicative（乘法的）operators.d.Case operators are formed by placing parentheses aroundthe name of a type.Local variables must be ________. ba.initialized when they are declared.b.initialized before their values are used in an expression.c.declared and initialized in two steps.d.declared at the top of the method.Which of the following code segments does not increment val by 3: ca.val += 3:b.val = val+1;val = val+1;val = val+1;c.c = 3;val = val + (c == 3 ? 2 : 3);d. All of the above increment val by 3.What does the expression x %= 10 do? ba.Adds 10 to the value of x, and stores the result in x.b.Divides x by 10 and stores the remainder in x.c.Divides x by 10 and stores the integer result in x.d.None of the above.What is the result value of c at the end of the following code segment? aint c = 8;c++;++c;c %= 5;a.0.b.1.c.3.d.None of the above.Keyword ________ represents the inheritance relationship. aa.extends.b.inherits.c.super.d.sub.Which statement prints the floating-point value 123.456 right justified with a field width of 10? da.System.out.printf( “%d10.3”, 123.456 );b.System.out.printf( “%10.3d”, 123.456 );c.System.out.printf( “%f10.3”, 123.456 );d.System.out.printf( “%10.3f”, 123.456 );For the code segment below,switch( q ){case 1:System.out.println( "apple" );break;case 2:System.out.println( "orange" );break;case 3:System.out.println( "banana" );break;case 4:System.out.println( "pear" );case 5:System.out.println( "grapes" );default:System.out.println( "kiwi" );} // end switchWhich of the following values for q will result in kiwi being output? ba.2.b.4 and anything greater than 4.c.1.d.3.。