The below code gives me compile time error Type mismatch: cannot convert from int to byte int i = 10; byte b = i; but the below doesn't final int i = 10; byte b = i; I don't understand why compiler is behaving in case of final? I think it's because 10 fits in a byte, but if the integer was something that takes more than 8 bits then it wouldn't be able to properly do this a
下面的代码给我编译时错误类型不匹配：不能从int转换为字节 int i = 10; byte b = i; 但下面没有 final int i = 10; byte b = i; 我不明白为什么编译器会在最终的情况下运行？ 我认为这是因为10适合于一个字节，但如果整数是需要多于8位的东西，那么它将无法再正确地完成这项任务。 编辑 为了澄清，最终让编译器将int视为一个常量，以便它可以进行不断的折叠。 它可能会阻止非最终int的赋值，因为它在编译时不知道
class ThrowNull { public static void main(String[] args) { throw null; } } We know that rule for throw is throw ThrowableInstance; , where ThrowableInstance must be an object of type Throwable or a subclass of Throwable. Simple types, such as int or char, as well as non-Throwable classes, such as String and Object, cannot be used as exceptions. null is a special Java literal w
class ThrowNull { public static void main(String[] args) { throw null; } } 我们知道throw的规则是throw ThrowableInstance; 其中ThrowableInstance必须是ThrowableInstance类型的对象或Throwable的子类。 简单类型（如int或char）以及非Throwable类（如String和Object）不能用作例外。 null是表示空值的特殊Java文字。 那么为什么要throw null; 在这段代码中编译？ 根据语言规范， throw语句被定
I am preparing for software interviews and i am stuck with a question for days now. I have not been able to figure out the difference between linkedhashmap, map, hashtable, hashmap present in the Java Collection API. Do all of these have the same get and put complexities? I know that map is the interface class and hashmap, hashtable, linkedhashmap implement this interface. So does that mean
我正在为软件访谈做准备，而且我现在仍然坚持着一个问题。 我一直无法弄清楚Java Collection API中存在的链接hashmap，map，hashtable和hashmap之间的区别。 所有这些都具有相同的复杂性吗？ 我知道map是接口类和hashmap，hashtable，linkedhashmap实现这个接口。 那么这是否意味着这三个类的内部实现是相同的？ 它们是如何在集合api中实现的？ 提前致谢！！！ 我怀疑这些差异可以被解释得比这些类的JavaDocs中已经写
I understood, I think, that a "Bean" is a Java class with properties and getters/setters. As much as I understand, it is the equivalent of a C struct. Is that true? Also, is there a real syntactic difference between a bean and a regular class? Is there any special definition or an interface? Basically, why is there a term for this? Edit : If you can be so kind and add informati
我明白，我认为，“Bean”是一个具有属性和getter / setter的Java类。 据我所知，它相当于一个C结构。 真的吗？ 另外，bean和普通类之间是否存在真正的语法差异？ 有没有特殊的定义或界面？ 基本上，为什么会有这样的术语？ 编辑 ：如果你可以如此善良并添加有关Serializable接口的信息，以及它的含义，对于你的回答，我会非常感激。 JavaBean只是一个标准 所有属性私有（使用getters / setters） 公共无参数构造函
the question is: How to create folders in google drive without duplicate? I'm answering the question in this post, and I want to share this code with anyone who is searching for a similar solution or problem to solve. the problem that I had, is how to create folders path in google drive without ending up with duplicates folders in the dirve! the first function used to check where the fo
问题是：如何在不重复的情况下在谷歌驱动器中创建文件夹？ 我在这篇文章中回答了这个问题，我想与任何正在寻找类似解决方案或问题的人共享此代码。 我遇到的问题是如何在谷歌驱动器中创建文件夹路径，而不会导致dirve中的重复文件夹！ 第一个函数用于检查文件夹的存在位置，传递驱动器实例和文件夹的标题，它是父母Id（不是标题）： /** * * @param service google drive instance * @param title the t
I use OpenNLP's coreference package for anaphora resolution. So basically I have this input string: "Harry writes a letter to his brother. He told him that he met Mary in London. They had a lunch together."; The set of mentions output are as below: Harry, his, He, him, he, They I need to replace the pronouns with its proper nouns. I wrote a simple algorithm for this by add
我使用OpenNLP的辅助包解决方案。 所以基本上我有这个输入字符串： “哈利写信给他的兄弟，他告诉他，他在伦敦遇见了玛丽，他们一起吃午餐。 提及的输出集合如下： 哈利，他，他，他，他，他们 我需要用它的专有名词来代替代词。 我为此写了一个简单的算法，将每个提到的元素添加到列表中，然后遍历列表，同时用第一个提及（“Harry”）替换每个代词。 我的问题是“他的”将是“哈利”而不是“哈利的”。 关于代词解析器的示
This question already has an answer here: What is a NullPointerException, and how do I fix it? 12 answers As per exception error is at line 57 ie table.setModel(null); And this is because you are initializing table at line 62 [table = new JTable();] and using it before that at line 57. It is a basic exception you face many time when you have null values in objects. Check for any null o
这个问题在这里已经有了答案： 什么是NullPointerException，以及如何解决它？ 12个答案 根据异常错误在第57行，即table.setModel（null）; 这是因为你正在初始化第62行的表[table = new JTable（）;]并在第57行之前使用它。 当你在对象中有空值时，这是你很多时候面临的基本异常。 检查程序中的任何空对象。 可能是你班上的第57行。 java.lang.NullPointerException at jtabledemo.Accounts.(Accounts.java:57) at
For some reason i dont know why my ComboBox cant be case on the button. Please help: Code: import java.awt.GridBagLayout; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.*; public class LocalBank implements ActionListener { JFrame frame; JPanel contentPane; JLabel label1; JLabel label2; JLabel label3; JTex
出于某种原因，我不知道为什么我的ComboBox不能按钮上的情况。 请帮忙： 码： import java.awt.GridBagLayout; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.*; public class LocalBank implements ActionListener { JFrame frame; JPanel contentPane; JLabel label1; JLabel label2; JLabel label3; JTextField accNumber;
I made a Mainmenu JFrame which can generate 4 different new frame represents each menu. Mainmenu frame was works fine. but I found that it could't get text from new frame textfield. here is error report and source code. please let me know how to fix it. import java.awt.BorderLayout; import java.awt.GridLayout; import java.awt.TextField; import java.awt.event.ActionEvent; import java.awt.
我做了一个Mainmenu JFrame，它可以生成4个不同的新框架代表每个菜单。 Mainmenu框架工作正常。 但我发现它无法从新的框架文本框中获取文本。 这里是错误报告和源代码。 请让我知道如何解决它。 import java.awt.BorderLayout; import java.awt.GridLayout; import java.awt.TextField; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowEvent; import java.awt.even
Cuando la ejecuto me marca este error `Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at ventana.VentanaPrincipal.actionPerformed(VentanaPrincipal.java:136) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at
错误：线程中的异常“AWT-EventQueue-0”在javax.swing.AbstractButton.fireActionPerformed（Unknown Source）处的ventana.VentanaPrincipal.actionPerformed（VentanaPrincipal.java:136）上的java.lang.NullPointerException .swing.AbstractButton $ Handler.actionPerformed（Unknown Source）at javax.swing.DefaultButtonModel.fireActionPerformed（Unknown Source）at javax.swing.DefaultButtonModel.setPressed（Unknow