blocks|key|38445|text|new+StudentForm();|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|38446|上面的变化只调用一个构造函数。|unstyled|38447|StudentForm+studentform=new+StudentForm();|38448|当您想要访问类中的构造函数以外的其他方法时，会使用上述变化。在这两种情况下，不管您是否使用studentform对象，构造器都将被调用。|offset|length|style|CODE|38449|例如，如果类具有名为methodOne()的其他方法|38450|public+class+StudentForm+extends+JFrame+{
++++public+StudentForm(){
++++++++setTitle("Admission+Form");
++++++++setSize(300,250);
++++++++setVisible(true);+++
++++}
++++public+void+methodOne()
++++{
+++++++++System.out.println("In+method+one..");
++++}
}|38451|然后您可以使用以下方法调用它：|38452|StudentForm+studentform=new+StudentForm();
studentform.methodOne();|38453|entityMap^0|0|0|0|19|B|0|A|B|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|Z|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|10|8|@]|9|@]|A|$B|C]]|$1|I|3|J|5|F|7|11|8|@$K|12|L|13|M|N]]|9|@]|A|$]]|$1|O|3|P|5|F|7|14|8|@$K|15|L|16|M|N]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|17|8|@]|9|@]|A|$B|C]]|$1|S|3|T|5|F|7|18|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|19|8|@]|9|@]|A|$B|C]]|$1|W|3|-4|5|F|7|1A|8|@]|9|@]|A|$]]]|X|$]]

<pre><code>new StudentForm();
</code></pre>

Above variation calls just a constructor.

<pre><code>StudentForm studentform=new StudentForm();
</code></pre>

Above variation is used when you want to access other methods than constructor in the class. In both the cases you contructor will be called regardless of you are using the <code>studentform</code> object or not.

For example if you class which has other method called <code>methodOne()</code>:

<pre><code>public class StudentForm extends JFrame {
 public StudentForm(){
 setTitle("Admission Form");
 setSize(300,250);
 setVisible(true); 
 }
 public void methodOne()
 {
 System.out.println("In method one..");
 }
}
</code></pre>

Then you can call it using:

<pre><code>StudentForm studentform=new StudentForm();
studentform.methodOne();
</code></pre>

blocks|key|3050258|text|new关键字表示StudentForm对象的instantiation/creation。所以|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3050259|new+StudentForm()|code-block|syntax|javascript|3050260|提供StudentForm的实例或简单的StudentForm对象。|3050261|唯一的区别是|3050262|StudentForm+studentform+=+new+StudentForm();

and+

new+StudentForm();|3050263|前者为新的reference对象提供了一个StudentForm。引用为studentForm|3050264|entityMap^0|0|3|8|B|M|M|0|0|2|B|K|B|0|0|0|5|9|L|B|10|B|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|17|8|@]|D|@]|E|$]]|$1|O|3|P|5|H|7|18|8|@]|D|@]|E|$I|J]]|$1|Q|3|R|5|6|7|19|8|@$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]|$9|1E|A|1F|B|C]]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1G|8|@]|D|@]|E|$]]]|T|$]]

The <code>new</code> keyword signifies the <code>instantiation/creation</code> of a <code>StudentForm</code> object. So

<pre><code>new StudentForm()
</code></pre>

gives you an instance of <code>StudentForm</code> or simply a <code>StudentForm</code> object.

The only difference between

<pre><code>StudentForm studentform = new StudentForm();

and 

new StudentForm();
</code></pre>

is that the former give you a <code>reference</code> to the new <code>StudentForm</code> object. The reference being <code>studentForm</code>

blocks|key|585672|text|守则：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|585673|StudentForm+studentform+=+new+StudentForm();|code-block|syntax|javascript|585674|构造一个新的StudentForm实例，并将对该实例的引用分配给变量studentform。以便以后可以调用StudentForm实例的方法，例如studentform.addContainerListener(xxx)。|offset|length|style|CODE|585675|但是代码new+StudentForm()只是调用构造函数来创建一个新的对象实例，但是不要保存对该实例的引用。|585676|entityMap^0|0|0|6|B|Y|B|1I|B|21|11|0|4|H|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]|$I|V|J|W|K|L]|$I|X|J|Y|K|L]|$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@$I|12|J|13|K|L]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$]]

The code:

<pre><code>StudentForm studentform = new StudentForm();
</code></pre>

constructs a new <code>StudentForm</code> instance and assign the reference to that instance to a variable <code>studentform</code>. So that you can call methods of the <code>StudentForm</code> instance later, such as <code>studentform.addContainerListener(xxx)</code>.

But code <code>new StudentForm()</code> just calls the constructor to create a new object instance, but don't hold the reference to that instance.

blocks|key|585722|text|StudentForm+studentform=new+StudentForm();|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|585723|您正在创建一个类型为StudentForm的对象，并将其分配给一个名为studentform的引用(在字段中使用camelCase，即studentForm而不是studentform+)。现在，您可以使用studentForm来调用对象的一些方法/访问字段。|585724|eg:+studentForm.toString()|585725|如果不能获得对对象的引用，则不能对该对象使用非静态方法。|585726|entityMap^0|0|16|0|0|0|Q|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Q|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|U|8|@]|D|@]|E|$]]|$1|L|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|M|$]]

<code>StudentForm studentform=new StudentForm();</code> 

You are creating an Object of type StudentForm and assigning it to a reference called studentform (use camelCase i.e, studentForm instead of studentform for fields). Now, you can use studentForm to call some methods/access fields of the object.

<code>eg: studentForm.toString()</code>

If you don;t get a reference to the object, you can't cal the non-static methods on that object.

blocks|key|3050343|text|保存已创建实例的引用的第一条语句和第二条语句没有对创建的对象的引用。除此之外，没有什么不同。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3050344|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Your First statement holding the reference of created instance, and the second statement don't have a reference for the created object. Other than this, there is no difference.

<pre><code>public class StudentFormMain { 
 public static void main(String[] args) {
 new StudentForm();
 }
}
</code></pre>

And 2ND Class

<pre><code>public class StudentForm extends JFrame {
 public StudentForm(){
 setTitle("Admission Form");
 setSize(300,250);
 setVisible(true); 
 }
}
</code></pre>

My Question are

What is the difference between these statements

<pre><code>StudentForm studentform=new StudentForm();
</code></pre>

and

<pre><code>new StudentForm()
</code></pre>

First Statement Declare the Obj of that class and calls the Constructor, but in Second Statement only Constructor is calling.

Note: Result are Same

<pre><code>super(""); set the title of the frame
</code></pre>

because it is calling super class constructor.
we can also set the title by using the <code>setTitle("")</code> method

Please differentiate the methods also.

Difference between these Constructor calling Statements?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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public class StudentFormMain {      public static void main(String[] args) {        new StudentForm();    }}二级和二级public class StudentForm extends JFrame {    pu...

问这些构造器调用语句之间的区别？
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问这些构造器调用语句之间的区别？EN