oracle interview questions for java developer

Oracle interview questions 1. Simple SQL query: 1): count the number of employees in each department Select Dept, count (*) from employee group by dept; 2): count the number of employees in each Department greater than one record Select Dept, count (*) from employee group by dept having count (*)> 1; 3): the name of the department where the employee whose salary

This article originates from: http://www.dbasupport.com The answer here is not very comprehensive, these questions can be explained through a number of angles, perhaps you do not have to give a full answer in the interview process, only through your answers to the interviewer to understand your understanding of the Oracle concept. 1. Explain the different points

create threads, how to create threads better (such as inheriting the thread class or calling the Runnable interface), and then gradually ask about concurrency problems like the Java memory model encountered in the process of Java concurrent programming, JDK1.5 introduces higher-order concurrency tools, common design patterns for concurrent programming, classic multithreading issues such as producer consume

Multithreading and concurrency issues are among the questions that interviewers prefer to ask in a Java technology interview. Here, the most important questions are listed from the interview point of view, but you should still have a solid grasp of the basics of

; k ) TestFunction (k, J, i);On the basis of scenario one, this scheme puts the instantiation of the cyclic variables out of the loop, which can further reduce the number of instances of the related cyclic variables, and the scheme time-consuming situation is as follows: Variable Instantiation (number of times) Initialization (number of times) Comparison (number of times) Self-increment (number of times) I 1 1 10 1

Java custom generic interview questions: receive any array to reverse, java custom You can only operate on a certain type for reversal without using the generic type. The Code is as follows: package com.swift.fanxing;import org.junit.Test;public class RenyiReverse { @Test public void test() { int arr[]=new

Do not write any scopes (that is, access rights) represent friendlyPublic, the largest, the largest scope, within the class, the same package, descendants class, other package can be accessedProtected protection, can be accessed within the class, the same package, descendant classes, but other package cannot accessFriendly friendly, within the class, the same package can be accessed, descendant class, other package cannot accessPrivate, minimal permissions, minimal scope, access within the class

). In the process of populating the handler, depending on your configuration, Spring will do some extra work for you: Httpmessageconveter: Converts the request message (such as Json, XML, and so on) to an object, converting the object to the specified response information. Data Transformation: Data conversion for a request message. such as string conversion to Integer, double, and so on. Data is initialized: Data is formatted for the request message. such as converting a string into a formatt

Collections.sychronizedlist to decorate a collection.In fact, vectors combine a set of "mutable arrays" and synchronize the implementation of each operation. This is another design flaw. Vector also has some legacy methods in enumerations and elements to get methods that are different from the list interface, if these methods in the code programmers tend to want to use it. Although enumerations are faster, they cannot be checked if the collection is modified during iteration, which can cause pr

Translation Links: http://www.codeceo.com/article/java-hashmap-value-sort.htmlThe English version: How to Sort HashMap Based on the Values in JavaTranslation Author: Code Rural network – Xiao Feng HashMap in Java is a data structure for storing "key" and "value" information pairs. Unlike array, ArrayList, and linkedlists, it does not maintain the order in which elements are inserted. Therefore, sorting hash

the length expands, the hash rules change as well. Let's review the hash formula:index = hashcode (Key) (Length-1) When the original array length is 8 o'clock, the hash operation is done with the 111B (representing the binary 7), and the new array length is 16,hash and 1111B (representing the binary 15). hash results are obviously different . The Java code for rehash is as follows: /** * Transfers all entries from the current table to newtable.

be accessed throughout the class.The ② member variable is created as the object is built, disappears as the object disappears, and exists in the heap memory where the object resides.The ③ member variable has a default initialization value.Local variables:① Local variables are defined only within the local scope, such as within a function, within a statement, and only in the area to which they belong.② local variables exist in the stack memory, the scope of the action ends, and the variable spac

Multithreading and concurrency issues are among the questions that interviewers prefer to ask in a Java technology interview. Here, the most important questions are listed from the interview point of view, but you should still have a solid grasp of the basics of

 original link Connection author : Pankaj translator : Zheng Xudong proofreading : Fang FeiMultithreading and concurrency issues are among the questions that interviewers prefer to ask in a Java technology interview. Here, the most important questions are listed from the intervi