单选题Which the statement is true？（）AThe Error class is a Runtime Exception.BNo exceptions are subclasses of Error.CAny statement that may throw an Error must be enclosed in a try block.Dany statement that may throw an Exception must be enclosed in a try blo

When any vessel fails to understand the intentions of an approaching vessel she must sound the danger signal

Only the stand-on vessel can sound the danger signal

Distress signals may be used in place of the danger signal

The danger signal consists of 4 or more short blasts of the whistle

They must be released by freeing a safety shackle

They should not be released until the boat is in lowering position

They may be adjusted by a turnbuckle

They are normally used only with radial davits

When at anchor，the pilot vessel is only required to sound anchor signals

The identification signal must be sounded any time the pilot vessel is underway

The pilot vessel may only sound the identity signal when making way

All of the above

Compass error and variation are equal

Compass north will be true north

Variation will equal deviation

There will be no compass error

 They are evaluated by all the three WHEN clauses regardless of the results of the evaluation of any other WHEN clause.

 They are evaluated by the first WHEN clause. If the condition is true， then the row would be evaluated by the subsequent WHEN clauses.

 They are evaluated by the first WHEN clause. If the condition is false， then the row would be evaluated by the subsequent WHEN clauses.

 The INSERT statement would give an error because the ELSE clause is not present for support in case none of the WHEN clauses are true.

All switch statements must have a default label.

There must be exactly one label for each code segment in a switch statement.

The keyword continue can never occur within the body of a switch statement.

No case label may follow a default label within a single switch statement.

A character literal can be used as a value for a case label.

 An anonymous inner class may be declared as final.

 An anonymous inner class can be declared as private.

 An anonymous inner class can implement multiple interfaces.

 An anonymous inner class can access final variables in any enclosing scope.

 Construction of an instance of a static inner class requires an instance of the enclosing outer class.

 the default log format can be used

 the fields%XC%X n must be appended to the default access log format

 any log format can beused ， but all WSAs must use the same format

 any log format can be used. And different WSAs may use different formats

Line 33 must be called within a try block.

The exception thrown by method 1 in class A is not required to be caught.

The method declared on line 31 must be declared to throw a runtime exception.

On line 5 of class A,the call to method 2 of class B does not need to be placed in a try catch block.

Compilation succeeds.

Class A does not compile.

The method declared on line 9 cannot be modified to throw TestException.

TestA compiles if line 10 is enclosed in a try/catch block that catches TestException.

 The Error class is a Runtime Exception.

 No exceptions are subclasses of Error.

 Any statement that may throw an Error must be enclosed in a try block.

 any statement that may throw an Exception must be enclosed in a try block.

 Any statement that may throw an Runtime Exception must be enclosed in a try block.

Error

Event

Object

Exception

Throwable

Runtime Exception

Key letters or abbreviations may not be used in GMDSS radio logbooks under any circumstance

Urgent communications do not need to be entered in the GMDSS radio log

Both of the above

None of the above