包含标签：Java 的文章
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Java – why mystring equals(“aString”); Different from “astring” equals(myString);?
I have heard many times that Boolean equals (object o) is used to compare strings. It is best to put the constant on t…… -
Java – the difference between loadclass (string name) and loadclass (string name, Boolean resolve)
What is the difference between loadclass (string name) and loadclass (string name, Boolean resolve)? The only differen…… -
How to check whether the class file version 50.0 (Java 6) has been pre verified?
I used Proguard to "upgrade" some jar files from class file version 49.0 to 50.0 Because pre validation is optional fo…… -
Print arrays in Java
I'm writing a method to print every object it passes By calling object The toString () method works, but not for array…… -
Java – bug about getbounds () and setbounds () on Linux_ Solution with id = 4806603?
On Linux platform, frame:: getbounds and frame:: setbounds cannot work consistently This was in 2003 (!) Report, see h…… -
java – MessageConsumer / MessageProducer vs QueueSender / QueueReceiver
Is messageconsumer / messageproducer equivalent to queuesender / queuereceiver? As far as I know, messageconsumer / me…… -
Java – polymorphism using Jackson to add subtype information at run time
I'm using Jackson to ungroup polymorphic types from JSON I use @ jsontypeinfo, @ jsonsubtypes and @ jsontypename annot…… -
Java – why can’t Tomcat find smtptransport (session, urlname)?
We have a web application that sends mail For some reason, its installation has decided that it cannot find the constr…… -
Java – multiple enumerations and one enum
When I stumbled upon something I didn't understand why, I was looking at the example implementation of publisher (asyn…… -
java – arrayListName. What does sort (null) do?
I have a project. The professor gave us some code There is a line in the code that puzzles me: arrayListName.sort(null…… -
Java – call thread What is the performance cost of isinterrupted()?
From the Java source code, it looks like native code Is the cost roughly equivalent to volatile reads or does it need …… -
Generic Dao in Java
I'm trying to develop a general Dao in Java I tried the following This is public abstract class AbstractDAO<T> …… -
Java – best practice for testing indexof return values
What do you usually write when testing the return value of indexof? if str.indexOf("a") < 0 VS if str.indexOf("a") …… -
Java – you cannot use expressions to increment byte values, but use the increment operator
See English answers > why byte + = 1 compile, but byte = byte + 1 not? 8 byte i=0; i++; The following is invalid by…… -
Strange behavior of Java scanner reading files
Therefore, I encountered an interesting problem when using the scanner class to read content from a file Basically, I'…… -
Java – what is the default temporaltype for temporal mapping keys without @ mapkeycolumn or @ mapkeytemporary annotations?
I am creating a JPA 2.0 annotation compliance kit for my internship I know that when you use @ mapkeycolumn to define …… -
ADO. Optimistic concurrency in net Entity Framework
I found that an MSDN article describes how EF handles concurrency when saving changes: I have two questions: >There…… -
Java – someone can explain spring security basepermission Create?
I'm developing a project involving spring security ACL, and I encountered creating permission basepermission CREATE. S…… -
Java – hibernate 5: generator class = “sequence” does not work properly
I have the following mappings: <id name="id" type="java.lang.Long" column="id"> <generator class="seq…… -
Java 9 repl for running applications
Java 9 introduced repl. Exe called jshell in the JDK distribution Is there any way to connect to the jshell of the JDK…… -
Criteria – multiple expressions in the JPA querybuilder where clause do not work
I'm using javax persistence. criteria. Criteriabuilder encountered a problem creating the query I am using eclipse lin…… -
Java – iterator of wildcard type variables with upper bound
Hello, I'm trying to extend HashMap < string, string > to enforce the "all lowercase" rule public class HttpQuer…… -
How to convert vectors in 1 row table in R
In R, I have a 1 - row table How do I convert it to a vector? Specifically, the table is as follows: 0 1 2 3 4 21…… -
Nutch: using java calls instead of the command line?
Am I thick or really unable to programmatically call Apache nutch through some java code? Where are the documents (or …… -
How to use java8 lambda expressions to throw exceptions for custom checks?
See English answers > java 8: lambda streams, filter by method with exception 13 private static void readStreamWith…… -
Java – create only one object for the class and reuse the same object
I want to create only one object of a class and reuse the same object over and over again How can I do this? Solution …… -
Java – change fonts of different lines in jtextarea
I want to add different font lines in jtextarea, but the last font seems to overwrite another font Please help import …… -
Java – Jenkins build fails with svnexception
I'm trying to run Jenkins build Here is my configuration Jenkins version: 1.445 deployment: as war Java: 1.7 (server 6…… -
Java – the key in treemap returns null
So I have a very strange mistake When I first used keyset () to iterate over the first 10 keys of a large treemap, I s…… -
Java – if there is no code: is it just an intellectual challenge or is it useful?
A friend of mine is discussing these design techniques for object state transformation (he is a Java master, by the wa…… -
Java – is it valid to get the logger from the static final variable initializer?
We have many class codes, and they have some templates as follows: private static Logger logger = null; private stati…… -
Java – ActiveMQ oom with stomp enabled
After enabling the stomp protocol on the ActiveMQ server (before it only enables the default protocol), it starts to f……