java面试题目（Java interview questions）.docVIP

java面试题目（Java interview questions） 1, can a.Java file contain multiple classes (not an internal class)? What are the restrictions? Answer: you can have multiple classes, but only one public class, and the public class can only be the same as the file name. 2, does Java have goto? Answer: Java in goto as reserved word, but not. Talk about the difference between the 3, and the . Answer: is the logic and the relationship between the side of the equation are true when it is true, or false, And has a short circuit function, if false expression is in front, so no calculation behind, this equation is false, if then back would have been executed Expression (str! =nullstr.equals ( )) if STR is null, no nullpointexception will appear, and if you change then there will be null pointer exceptions. When both sides of an expression are not Boolean types, they can be bitwise and operation 4. How do you jump out of the current multiple nested loops in JAVA? Answer: you can define OK: then recycle, make a conditional limit, jump out with break, the code is as follows System.out.println (begin); Ok: For (int i=1; i10; i++) { For (int, j = 0, J, 10, j++) { System.out.println (i=, +i+, ----------j=, +j); If (i==2j==3) { Break ok; } } } System.out.println (end); Can the 5 and switch statements work on byte and can they work on the long? Can it work on the String? Answer: there are int, short, byte, and some enumerated types that can be used in switch Switch (color) { Case yellow: Color=yellow; Break; Case red: Red; Break; Case green: Color=green; Break; } 6, short S1 = 1; S1 = S1 + 1; whats wrong? Short S1 = 1; S1 = 1; whats wrong? Answer: 1.s1+1 will automatically upgrade to the int type, and error when assigned to S1 2.+= is an operator defined in the Java language, and the java compiler handles it specifically so that it can be compiled correctly Can you store a Chinese character in the 7 and char variables? Why? Answer: Yes, and you can store just one Chinese character! cha