Recent questions tagged java

0 votes

510 views

1 answer

java - Buiding Hadoop with Eclipse / Maven - Missing artifact jdk.tools:jdk.tools:jar:1.6

I am trying to import cloudera's org.apache.hadoop:hadoop-client:2.0.0-cdh4.0.0 from cdh4 maven repo in a maven ... :jar:1.6 How to solve this? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

275 views

1 answer

java - Avoid printStackTrace(); use a logger call instead

In my application, I am running my code through PMD.It shows me this message: Avoid printStackTrace(); use a ... instead. What does that mean? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

98 views

1 answer

java - How can I replace two strings in a way that one does not end up replacing the other?

Let's say that I have the following code: String word1 = "bar"; String word2 = "foo"; String story = " ... foo." How could I accomplish that? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

283 views

1 answer

java - Graphing the pitch (frequency) of a sound

I want to plot the pitch of a sound into a graph. Currently I can plot the amplitude. The graph below is created ... there a way I can do this? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

198 views

1 answer

java - Graph Visualisation (like yFiles) in JavaFX

Something like Graphviz but more specifically, yFiles. I want a node/edge type of graph visualization. I was thinking ... . Thanks for the help. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

125 views

1 answer

java - Android Intent Context Confusing

Can somebody explain this to me please : Intent intent = new Intent(Context, AlarmReceiver.class); I never ... right one in every situation? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

126 views

1 answer

java - IntelliJ IDEA way of editing multiple lines

I've seen this done in TextMate and I was wondering if there's a way to do it in IDEA. Say I have the ... easy way to right justify the text :P See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

150 views

1 answer

java - Why the odd performance curve differential between ByteBuffer.allocate() and ByteBuffer.allocateDirect()

I'm working on some SocketChannel-to-SocketChannel code which will do best with a direct byte buffer--long lived and ... Thread.sleep(200); } } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

214 views

1 answer

java - What could cause global Tomcat/JVM slowdown?

I'm experiencing a strange but severe problem running several (about 15) instances of a Java EE-ish web applications ( ... manual timing in the browsers, so it's not the mo...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

124 views

1 answer

java - What are Dynamic Proxy classes and why would I use one?

What is a use case for using a dynamic proxy? How do they relate to bytecode generation and reflection? Any recommended reading? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

176 views

1 answer

java - Declaring multiple arrays with 64 elements 1000 times faster than declaring array of 65 elements

Recently I noticed declaring an array containing 64 elements is a lot faster (>1000 fold) than declaring the ... to circumvent this problem. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

117 views

1 answer

java - Why an interface can not implement another interface?

What I mean is: interface B {...} interface A extends B {...} // allowed interface A implements B {... ... , interface B = %100 abstract class B See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

284 views

1 answer

java - How to tell if JRE or JDK is installed

I have one computer that I intentionally installed JDK on. I have another computer with JRE, for, among other things, ... in question is a Mac. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

174 views

1 answer

java - Reuse a parameter in String.format?

String hello = "Hello"; String.format("%s %s %s %s %s %s", hello, hello, hello, hello, hello, hello); ... applied to all of the %s tokens? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

199 views

1 answer

java - Why do spring/hibernate read-only database transactions run slower than read-write?

I've been doing some research around the performance of read-only versus read-write database transactions. The ... other comments? Thanks much. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

212 views

1 answer

java - Reason for calling shutdown() on ExecutorService

I was reading about it quite a bit in the past couple of hours, and I simply cannot see any reason ( ... to share their experiences. Thanks. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

251 views

1 answer

java - side effect for increasing maxpermsize and max heap size

Can anybody explain the side effects for increasing the maxpermsize and max heap size? I know that sometimes, we ... affect the runtime? Thanks. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

320 views

1 answer

java - Mocking member variables of a class using Mockito

I am a newbie to development and to unit tests in particular . I guess my requirement is pretty simple, but I am ... that I want to test . ? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

105 views

1 answer

java - Get boolean from database using Android and SQLite

How can I obtain the value of a boolean field in an SQLite database on Android? I usually use getString(), ... to be a getBoolean() method. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

136 views

1 answer

java - How to refresh JPA entities when backend database changes asynchronously?

I have a PostgreSQL 8.4 database with some tables and views which are essentially joins on some of the tables ... key to work properly). See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

179 views

1 answer

java - JBoss AS 7: How to clean up tmp?

I noticed that in my JBoss Application Server 7 installation under standalone/tmp I have 400 MB of files related ... all those files myself? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

202 views

1 answer

java - Why do JVM arguments start with "-D"?

Why do we need to prefix JVM arguments with -D e.g. when running a jar from the command line? E.g. java -jar ... -D what does the D stand for?. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

351 views

1 answer

java - @UniqueConstraint and @Column(unique = true) in hibernate annotation

What is difference between @UniqueConstraint and @Column(unique = true)? For example: @Table( name = " ... ) private Group group; See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

199 views

1 answer

java - Best Practice: Initialize JUnit class fields in setUp() or at declaration?

Should I initialize class fields at declaration like this? public class SomeTest extends TestCase { private final List ... must be a reason. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

301 views

1 answer

java - How to convert nanoseconds to seconds using the TimeUnit enum?

How to convert a value from nanoseconds to seconds? Here's the code segment: import java.io.*; import ... instantiated. What does this mean? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

469 views

1 answer

java - Arrays.asList() vs Collections.singletonList()

Is there an advantage (or much of a difference) to using Arrays.asList(something) over Collections.singletonList( ... list immutable as well. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

97 views

1 answer

java - IntelliJ does not show 'Class' when we right click and select 'New'

We're creating a new project in IntelliJ and must have something wrong because when we right click on a ... ourselves when we discovered this' See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

257 views

1 answer

java - Young , Tenured and Perm generation

I'm confused with Heap,Young,Tenured and Perm generation. Could anyone please explain? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

Categories

Just Browsing Browsing

Most popular tags