包含标签：Java 的文章
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In Java, can I use conditional expressions to “select” reference types?
Can I use conditional expressions to "select" reference types, as shown below? ??? = isTrue() ? Integer : Double; What…… -
Convert CIDR notation to IP range in Java
See the English answer > converting CIDR address to subnet mask and network address 11 For example, for CIDR 192.16…… -
Java – how to use spring roo to create @ entity without @ version field?
I use spring roo and JPA (hibernate) as my entity model I don't want to have a @ version field in some entities How ca…… -
How to use java to find data in small data sets?
We have to find some data according to three input data fields Search must be fast There are only about 20 possible se…… -
How to override generic list return types in Java
I tried to override a method whose return type is a list in a subclass, as shown in the following example. Due to gene…… -
Strange Java HashMap behavior – no matching object found
When I tried in Java util. When I found a key in HashMap, I encountered some strange behavior. I think I missed someth…… -
Java findbugs: suspicious comparison of long references
Findbugs identified the following error in my code: @ h_ 404_ 7@ if (materialDeFinition.getId() == deFinitionToRemoveF…… -
Java – when deploying spring app in Tomcat 6, an “access denied” message appears
When I tried to deploy my spring application on Tomcat 6, I received an error message java.util.logging.errormanager:4…… -
Java – what did I do wrong with this quadratic formula?
a = 1,b = -7,c = 12 a = 1,b = -7,c = 12 public static void quadratic(double a,double b,double c){ double r1; …… -
Java – a term that distinguishes between “default” and “makeup” classes in OOP
ArrayLists, buffer readers, scanners, etc All default classes that already exist in the language Unlike the public cla…… -
Java – regular expression or exception handling?
Which of the following is better to check whether the string is floating? try{ Double.parseDouble(strVal); }catch(Num…… -
Java – how to add icons to items in the navigation drawer
I want to place icons next to items in my navigation drawer. I have set such icons: Titles = getResources().getStringA…… -
How to use java to find data in small data sets?
We have to find some data according to three input data fields Search must be fast There are only about 20 possible se…… -
Datamapper – doctrine2 best practice, should entities use services?
I answered a similar question: using the data mapper pattern, should the entities (domain objects) know about the mapp…… -
Java – declare anonymous inner classes
rb.addActionListener(new ActionEvent(ae) { rb.addActionListener(new ActionEvent(ae) { public void actionPerformed(A…… -
Java says this method has a constructor name
I want to return the value of my array plus the return value of the recursive call But for some reason, Java doesn't w…… -
Parsing timestamp with time zone in Java?
I'm trying to parse a string of time stamps using the time zone obtained from DB The string is as follows: SimpleDateF…… -
Java – Method Parameter confusion
Usually, time methods require more than 3 parameters of the same type, such as void mymethod (String param1,String par…… -
Java – which implementation is better: a cache based on weakhashmap or a cache based on ThreadLocal?
It's hard for me to decide between the following two implementations I have written two POC implementations and am gla…… -
Java – can class types be passed and used as return types?
I have a method to use the parser. The example of parser call is: SpecificClass ret = parser.parse(getOutputStream(),S…… -
How to interrupt a thread blocked by some socket IO operations without closing
I really want to know how to interrupt a thread blocked by some I / O operation? I / O is through socket, I don't want…… -
Array. In Java What is the internal code for length()?
What is stored in the 10th position of the array int[] array=new int[10]; Suppose we have values stored from array [0]…… -
Java – wait () is an “if” block or a “while” block
See English answers > why should wait() always be called inside a loop I've seen many examples of using a while loo…… -
Java – coding guide for case of numeric text suffix
I did some Googling, but I couldn't find a solution to my problem According to the double and float declarations, are …… -
In Java, is it an existing object on the heap?
In Java, is it an existing object on the heap? I try to understand the difference between an uninitialized local varia…… -
Java – calculate occurrences in Multimap
I have a Multimap with multiple similar values: {Entertainment=[5],Food=[2,2,2],Products=[11],Health & Beauty=[3]}…… -
Does the Java optimizer remember calculated values?
Which fizzbuzz implementation is more efficient? public static void fizzBuzz1(int n) { boolean fizzed,buzz…… -
Is there a detect method from Smalltalk in Java?
I search for method detection in Java 8 I used to use it in Smalltalk, but Java doesn't seem to have it Smalltalk's de…… -
Need help understanding the following Java syntax
public void printPixelARGB(int pixel){ public void printPixelARGB(int pixel){ int alpha = (pixel >> 24) & …… -
Java: what is the correct way to convert a string to a valid amount (BigDecimal)
I must convert the incoming string field to a BigDecimal field representing a valid amount, for example: String amount…… -
Java – redraws JPanel only after window resizing is complete
I have a JPanel and I draw four rectangles on it Randomly select the color of each of these rectangles The color chang…… -
How does this multithreaded java code work?
In view of this, the Java code: class Account { private Integer number = 0; public synchronized void s……