Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p><strike>Objects are passed by reference by default</strike> Objects are <strong>accessed</strong> by reference, but there is no way to create a reference to a primitive value (byte, short,int, long). You either have to create an object to wrap the integer or use a single element array.</p> <pre><code>public void sum(int[] i){ i[0] = ...; } </code></pre> <p>or </p> <pre><code>public void sum(MyInt i){ i.value = ...; } public class MyInt{ public int value; } </code></pre> <p>for your example something like the following could work</p> <pre><code>public int sum(int v){ return ...; } </code></pre> <p>or</p> <pre><code>public int sum(){ return ...; } </code></pre> <p><strong>Update:</strong></p> <p>Additional/Better description of object references:</p> <p>Java Objects are always accessed by a reference. Like the primitive types this reference is passed by value (e.g. copied). Since everything a programmer can access in java is passed by copying it (references, primitives) and there is no way to create a reference to a primitive type, any modification to a method parameter (references, primitives) only affects the local copy within the method. Objects can be modified within a method since both copies of the reference (local and other) still point to the same object instance.</p> <p>example:</p> <p>Modify a primitive within method, this only affects the internal copy of i and not the passed value.</p> <pre><code>void primitive(int i){ i = 0; } </code></pre> <p>Modify a reference within method, this only affects the internal copy of ref and not the passed value.</p> <pre><code> void reference(Object ref){ ref = new Object();//points to new Object() only within this method } </code></pre> <p>Modify an object, visible globally</p> <pre><code>void object(List l){ l.add(new Object());//modifies the object instead of the reference } </code></pre> <p>Both the array and MyInt above are based on the modification of an object.</p>
    singulars
    1. This table or related slice is empty.
    1. POHow to use references in Java?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USjosefx
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POHow to use references in Java?
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTDownMod
    1. CO"Objects are passed by reference by default" - That's wrong. Everything is pass-by-value in Java. Where it gets confusing is that **references** (non-primitive variables) are also passed **by value**. Note that passing a reference by value is not the same as passing an object by reference.
      singulars
      1. PO
      1. USJesper
    2. CO@Jesper it's not completely wrong, objects are always passed by reference in java. That the reference itself is passed by value is also true.
      singulars
      1. PO
      1. USjosefx
    3. COYou cannot directly pass objects. Variables of non-primitive types are references - they are not the objects themselves, as in C++. Talking about "passing objects" is imprecise terminology when you're talking about Java.
      singulars
      1. PO
      1. USJesper
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload