electromagnetism questions and answers

single-threaded program can not produce OutOfMemoryError exception, using multithreading will also appear outofmemeoryerror, because the stack is thread-private, line multithreading also overflow method area3, JVM stack space allocation over the General Assembly caused by what problemshttp://blog.csdn.net/qq_30739519/article/details/510425844. How to detect dead loops and deadlocks in the JVMDeadlock: http://www.cnblogs.com/ilahsa/archive/2013/06/03/3115410.htmlDead Loop: http://blog.csdn.net/s

value is: 2147483647, binary: 01111111111111111111111111111111The minimum value is:-2147483648, binary: 10000000000000000000000000000000and the binary positive and negative conversion method is anti-code +1, anti-code is the positive code of all the digits of the 0 and 1 swap.-2147483648 Binary Positive code:10000000000000000000000000000000-2147483648 binary Anti-code:01111111111111111111111111111111-2147483648 binary Anti-code + 1:10000000000000000000000000000000After a long day back, so Math.

synchronized, they can be entered. 21. When an object is passed as a parameter to a method, this method can change the properties of the object and return the changed result, so is it a value pass or a reference pass? In Java, only the value is passed, and if the object is passed, the address of the object is actually passed. 22. Scope public,private,protected, and the difference between non-write public modifier, which means any class can be accessed. Protected is a protected modifier that rep

tee filter?Answer: The tee filter is used to send output to multiple destinations. If used for pipelines, it can copy the output to one file and copy the other to the screen (or some other program).[Email protected]:~$ ll/etc | NL | Tee/tmp/ll.outIn the example above, the LL output can be captured in the/tmp/ll.out file and also displayed on the screen.Q: Export PS1 = "[Email protected]:\ $PWD: What is this command doing?]A: This export command changes the login prompt to display the user name,

on another thread's message, and waits until the message arrives when it does not get another thread's message.Thread mutex refers to the exclusive nature of the shared process system resources when each individual thread accesses it. When there are several threads that want to use a shared resource, at most one thread is allowed to use at most, and other threads that want to use that resource must wait until the resource is freed by the resource. Thread mutexes can be seen as a special kind of

Server and so on.2. Under the premise of not destroying the 1 deployment, also use Oldboy user to complete multiple keys to a lock (B,c key, a lock)-Free landing deployment as follows:B---------->aC---------->aNote: This topic is used in the production environment, data backup, etc., but the production environment this way is recommended to be implemented by the daemon process.The goal of the final realization is, 1, 22 topics to achieve two-way password-free authentication login.3. If you incr

and executed successively. Even in multithreaded mode, all commands are atomic unless the program has a bug:)The command sequence is not atomic. If you get an item with a GET command, modify it, and then want to set it back to memcached, we don't guarantee that the item is not manipulated by another process (process, not necessarily an operating system). In the case of concurrency, you may also overwrite an item that is set by another process.Memcached 1.2.5 and later, the Get and CAS commands

? What is Futuretask? How to wake up a blocked thread? How do immutable objects help with multithreading? What does multi-threaded context switching mean? What thread scheduling algorithms are used in Java? What is the role of Thread.Sleep (0)? What is the Java memory model, which areas are thread-shared, and which are unshared What are optimistic and pessimistic locks? Why do I synchronize the size () method of the Hashtable? Synchronization methods and synchronization block

++;Parent.printvalue ();　　((child) parent). myvalue++;Parent.printvalue ();}}Operation Result:Summarize:When a subclass has the same method as the parent class, and a parent class variable refers to a subclass object, which method is called, determined by the object's own "true" type, that is, the object is a subtype, it calls the method of the subtype, it is the parent type, and it invokes the method of the parent type. This feature is actually a concrete representation of the object-oriented "

class hello{public static void Main (string[] ARS) {A ab = new B (); Executed here, results: 1a2bAB = new B (); Executed here, results: 1a2b2b}}A: the output is 1a2b2b; the static code snippet for a class can be thought of as code executed by the class for the first load (virtual machine load), and for class loading, the first thing to do is to execute the construction of its base class, and then perform its own construction.50, the Succession time class execution order question, generally is t

as the struts,spring MVC framework, which cleanly isolates business objects and control logic with control inversion. It also allows binding of request parameters and business objects in a declarative manner.Dispatcherservlet.The Spring MVC Framework is designed around Dispatcherservlet to handle all HTTP requests and responses.Webapplicationcontext.Webapplicationcontext inherits ApplicationContext and adds some unique features to the Web application that are different from the general Applicat

The main points of installing a dual operating system are: (1) disk planning, note that dual operating systems should be installed in different partitions, (2) for beginners, it is best to install from a low to a high version; (3) Boot.ini, Ntdetect and Mldr These three files are very important for the boot of the dual operating system, and a backup is usually available. If you want to install 3 or more systems on your computer, it's easy to do so, as long as you plan your partitions and then i

Tags: sql face question SQL exerciseStructure of the tableStudent (s#,sname,sage,ssex) Student tableCourse (c#,cname,t#) timetableSC (s#,c#,score) score tableTeacher (t#,tname) Teacher table 1. Creating the corresponding table CREATE table student (' s# ' int, sname varchar (+), Sage int, s Sex varchar) The following omit 2. Inserting data insert into student Select 1, ' Zhang San ', 18, ' Male ' union ALL select 2, ' John Doe ', 18, ' Male ' Unio n all .... 3. Check the number of all stud

Label:1. Query the sname, Ssex, and class columns of all records in the student table. Select T.sname,t.ssex,t.sclass from student t; 2, the inquiry teacher all units namely does not duplicate depart column. Select * from teacher T where t.depart= ' computer system '; 3. Query all records of student table. Select *from student T; 4. Query all records from 60 to 80 of the scores in the score table. SELECT * FROM Student t where T.sno in (select E.sno from score e where degree between and 80);

, PDB1)Extract E1 successfully registered with database at SCN 2664333.Sql> select Capture_name,capture_user,status,start_scn,purpose from Dba_capture;Capture_name capture_user STATUS START_SCN PURPOSE----------------- ------------------ -------- ---------- -------------------Ogg$cap_e1 C # #GGADMIN ENABLED 2664333 GoldenGate Capture(3) testSql> Connect Pdb1_u1/[email protected]Connected.1) DMLsql> INSERT into S1 values (+);1 row created.Sql> commit;Commit complete.2) DDLsql> Create sequence SS1

Hong Kong or somewhere), after the server C to jump directly to the appropriate server. Statistics are combined with data from three machines.7 Starting now requires that the same IP cannot be repeated, please indicate how to modify the data table accordinglyALTER TABLE ' Phpinterview '. ' Poll ' ADD unique INDEX ' ix_poll_ip ' (' IP ');8. The original data already has a lot of duplicate IP data, so we export it to a TXT, the format and the top of the poll consistent, with the TAB key interval,

difference between a green thread and a local thread in Java? 2) What is the difference between threads and processes? 3) What is context switching in multi-threading? 4) What is the difference between a deadlock and a live lock, the difference between a deadlock and a pie? 5) What is the thread scheduling algorithm used in Java? 6) What is thread scheduling in Java? 7) How do you handle non-catching exceptions in the thread? 8) What is a thread group and why is it n

Answers to questions about how to collect relevant materials during graduation project (Chen Xiaowei's early articles) During graduation design, most people want to take advantage of this last opportunity to learn something practical, or prepare for a job. However, when I did it, I found that my graduation project seemed to have no way to start, or I coul

Promise object that outputs1 Result +1, now the output is2 The output is discarded and an error is thrown Error is discarded, returning a new value ( 1 ) Catch performs exception handling, but the program does not stop after a catch, returning a message after +1 of value ( 2 ) Value Normal output Value is output normally, This line does not execute spending time with one day is more effective than technical questioningIt is more valuable to spend at least half a day

51cto college specially sorted out "2014 network administrator-exam exercise Questions and Answers" in the soft exam preparation season to help schools pass smoothly! For more software proficiency test counseling and questions, please pay attention to the 51cto college-soft exam classification! View summary:Exercise question