core java interview questions for experienced

;. java.util Package: Java Utility Class Library Java.util package. In this package, Java provides some useful methods and data structures. For example, Java provides a date (Data) class, a calendar class to produce and get dates and times, a random number class that produces random numbers of various types, and a stack (stack), vector, bit set (Bitset), and a ha

COSCO Java interview question zzz COSCO Java interview questions Java training materialsI. Java language1. Three basic features of object-oriented2. Concepts and differences between met

) Select the correct collection type as needed. For example, if you specify a size, we will choose an array instead of a ArrayList. If we want to traverse a map in order of insertion, we need to use TreeMap. If we don't want to repeat, we should use set.(2) Some collection classes allow you to specify the initial capacity, so if we can estimate the number of stored elements, we could use it to avoid re-hashing or resizing.(3) programming based on interfaces, rather than implementation-based prog

TreeMap. If we don't want to repeat, we should use set.(2) Some collection classes allow you to specify the initial capacity, so if we can estimate the number of stored elements, we could use it to avoid re-hashing or resizing.(3) programming based on interfaces, rather than implementation-based programming, allows us to easily change the implementation later.(4) Always use type-safe generics to avoid classcastexception at run time.(5) Using the immutable classes provided by the JDK as key to t

)Analysis: When a class is loaded, from the parent class to the subclass, from top to bottom, execute the static code block, and then execute the main function , if there is a statement of the new object, The construction code block and constructor of the binding are executed. Note: static code blocks have and execute only once14. What is the result of the following code?public class a{public static void Main (string[] args) {String str;System.out.println ("" + str);}}Analysis: The above code w

block first, and the post constructor)Parse: When a class is loaded and finished, from the parent class to the child class. From top to bottom. Run the static code block first, then run the main function , and if there is a statement for the new object, run the bound construction code block and constructor. Note: static code blocks are available and run only once14. What is the execution result of the following code?public class a{public static void Main (string[] args) {String str;System.out.

Java Exception Common interview question one, Java exception understandingExceptions are mainly handling errors that cannot be caught at compile time. The problem can continue to execute smoothly, without causing the program to terminate, to ensure the robustness of the program.Processing: When an abnormal state is generated, if the current context does not have

after the real object is called.Proxy mode,The proxy class and the proxy class implement the same interfaceAn instance of a proxy class in a proxy classBehavioral patterns: Focus on communication between objectsSuch as: Responsibility chain mode, iterator mode, command modeResponsibility chain ModelSimilar interceptors, etc.Command mode:Separates callers from Callee's behaviorInterpreter mode:Each syntax is an interpreter classIterator mode:Change the collection class's view traversal and add a

adapter pattern? Ø database How are you usually optimized, what other tools are used to optimize no, how to use the Ø Now there is a lot of tables to correlate the query SQL, the child table data is very much, then you only from the SQL point of view of the SQL statement optimization, do not need to consider the index, predicate Ø you don't have a Java project, do you? Ø your major is to control the direction, why do the current direction O you have

Java and C common technical interview questions 2015 (Continuous updates ...), 2015 updating 1. Differences between overwrite and overload Overload is an Overload. It uses the same name as an existing member to declare attributes or methods, but the parameter list is different from that of the original member. Override is mainly used for method rewriting between

. 245 page71 Video 8.6 Viewer mode for linkage Scenarios 8.4.3 page No. 25172 Video 8.7 Applying a dependency reversal principle can reduce the range of changes affected 8.5.1 No. 254 page73 Video 8.8 A single responsibility principle that can keep classes as stable as possible 8.5.2 No. 256 page74 Video 8.9 The Richter replacement principle to follow when inheriting 8.5.3 No. 257 page75 Video 8.10 Optimizing inherited usage scenarios by using the synthetic Multiplexing Principle page No. 261 of

wrapper type , which means that the wrapper type can be converted directly to the base data type , as shown in the following code:int m=100; Integer im=int N=im; The appeal code directly assigns m to the wrapper object IM, which is automatically boxed and then directly assigns the IM to the basic data type N, which is the automatic unpacking. Although the code on the surface is simple and convenient, however, in essence, the container still uses new to create the object, while unpacking is s

I used to have only one Java interview question topic. Now I have divided into the following topics: Java interview questions are of course the focus, all of which are Java programming and directly related to the design. Intelli

Dark Horse programmer ---- java-based operators, keyboard input, if switch statements, related Interview Questions, ---- javaswitch ------ Java training, Android training, iOS training, and. Net training. We look forward to communicating with you! ------- 1: Operator (master)(1) Arithmetic Operators A: +,-, *,/, %, ++

Transferred from: http://icyfenix.iteye.com/blog/715301The background of this post is tonight to see JE on this posting: http://www.iteye.com/topic/715256, the words written on impulse, if you can, can have other interviewers to analyze their interview questions asked, it may be a very meaningful thing. In the company as a technical interviewer for a few years, from graduating students to work more than 10

In the Java Pure Grammar interview, mainly encountered some of the basic interview questions, summarized here!First, to talk about final, finally, finalize the difference. final-modifier (keyword) If a class is declared final, it means that it can no longer derive a new subclass and cannot be inherited as a parent c

Android development interview: 4. Common basic Java questions, androidjava Follow finddreams blog: http://blog.csdn.net/finddreams/article/details/44403041Because Android is programmed using the Java language, it is necessary for us to fully master the Java foundation for A

Java Multithreaded interview questions 1. What is the difference between processes and threads? A process is a stand-alone (self contained) operating environment that can be viewed as a program or an application. A thread is a task that is performed in a process. The Java Runtime environment is a single process that

take out 1 position: Product: 4 The consumer takes out from 0 position: Product: 2 producer put in 0 position: Product: 5 consumer removed from 0 Position: Product: 5 producer put in 0 position: Product: 6 consumer is removed from 0 position: Product: 6 producer put in 0 Location: Product: 7 producer puts 1 position: products £ º The producers are placed in the location of the product: 8 Position: Product Consumer removed from 1 position: Product: 9 consumer removed from 0 positions: Products:

) {MapNewHashmap(); Premiumphone.put ("Apple", "IPhone"); Premiumphone.put ("HTC", "HTC One"); Premiumphone.put ("Samsung", "S5"); Iterator Iterator=Premiumphone.keyset (). iterator (); while(Iterator.hasnext ()) {System.out.println (Premiumphone.get (Iterator.next ())); Premiumphone.put ("Sony", "Xperia Z"); } } }"Main" java.util.ConcurrentModificationException at java.util.hashmap$hashiterator.nextentry (Unknown SOURCE) at Java.util.hashmap$keyiterator.next (Unknow