autoboxing Questions
8
Solved
I'm implementing an interface that has functionality similar to a table that can contain an types of objects. The interface specifies the following function:
double[] getDoubles(int columnIndex);...
Been asked 10/7, 2009 at 14:46
1
Solved
There is the following code:
Integer time = 12;
Double lateTime = 12.30;
Boolean late = false;
Double result = late ? lateTime : time; //Why here can I assign an Integer to a Double?
System.out.pr...
Delaunay asked 23/1, 2017 at 10:19
4
I found a piece of code that after switching from Java 7 to Java 8 stopped compiling. It does not feature any of the new Java 8 stuff like lambda or streams.
I narrowed the problematic code down t...
Mo asked 11/1, 2017 at 11:43
5
Solved
What is the most preferred way of converting a String to Long (the Object) in Java.
Long a = new Long(str);
OR
Long a = Long.parseLong(str);
Is there a correct way here because both see...
Hefty asked 29/9, 2016 at 14:57
8
Solved
Let's look at the simple Java code in the following snippet:
public class Main {
private int temp() {
return true ? null : 0;
// No compiler error - the compiler allows a return value of null
...
Lengel asked 11/11, 2011 at 19:30
1
Solved
In my software, I have some various values which use property delegation.
This is a simple similar example showing what I do:
class ExampleDelegate<T>(val value: T) {
operator fun getValu...
Thad asked 25/8, 2016 at 18:20
3
Solved
What is the difference between the following:
Integer in = (Integer)y;
and
Integer in = new Integer(y);
I want to convert int type to Integer type and vice versa. Here is my code for doing that...
Zaragoza asked 4/7, 2016 at 5:53
2
Solved
We are using axis2 to generate web-service clients, (I regret this now!). With axis2 command-line tool you can pass switch -Euwc to wrap int into Integer, boolean into Boolean and so on in generate...
Parenthesize asked 31/5, 2011 at 14:21
10
Solved
I have a method like this:
public static <T> boolean isMemberOf(T item, T[] set)
{
for (T t : set) {
if (t.equals(item)) {
return true;
}
}
return false;
}
Now I try to call this met...
Kyongkyoto asked 5/2, 2009 at 20:24
4
Solved
Why does this throw NullPointerException
public static void main(String[] args) throws Exception {
Boolean b = true ? returnsNull() : false; // NPE on this line.
System.out.println(b);
}
public...
Imbecility asked 7/10, 2010 at 13:28
3
I'm working on a program that deals constantly with gigabytes of data, mostly primitives and strings. I need to avoid having the primitives converted to Objects by autoboxing as this explodes the h...
Doctrinaire asked 19/3, 2016 at 23:32
5
Solved
Consider the following example:
public static void main(String[] args) {
double x1 = 0.0, y1 = -0.0;
Double a1 = x1, b1 = y1;
System.out.println(x1 == y1); //1, true
System.out.println(a1.equa...
Indicatory asked 17/3, 2016 at 5:21
2
Solved
So I understand you can have object streams, i.e. Stream<T> and specialist primitive streams, e.g. IntStream, DoubleStream, etc. One of the benefits of the latter is to avoid autoboxing.
Al...
Item asked 4/2, 2016 at 18:49
1
Solved
Is it the compiler or the runtime do the auto-boxing/unboxing?
Consider the following example:
public Integer get() {
return 1; //(1)
}
At (1), the primitive integer value will be converted in...
Dosser asked 28/1, 2016 at 7:30
1
Solved
Say I have the following code:
Map<String, Boolean> map = ...
map.put("foo", true);
Theoretically, true will have to be autoboxed, resulting in a slight performance hit versus inserting Bo...
Pseudohermaphroditism asked 8/1, 2016 at 23:8
0
When I put this into my avro schema:
{ "name": "the_id", "type": "int" },
And then I:
mvn generate-sources
A class file is generated that contains the following:
private int the_id;
/**
* Al...
Weightlessness asked 18/12, 2015 at 14:27
15
Solved
I know there are similar posts on the topic, but they don't quite address my question. When you do:
Integer a = 10;
Integer b = 10;
System.out.println("a == b: " + (a == b));
This will (apparent...
Hydrocellulose asked 11/3, 2011 at 20:20
5
Solved
Please regard the following lines of code:
public static void main(String[] args) {
foo(1,2,3);
System.out.println("-------------------------------------");
foo(new Integer(1), new Integer(2), ...
Inherence asked 3/12, 2015 at 8:31
4
I'm trying to determine whether the following statements are guaranteed to be true:
((Boolean)true) == Boolean.TRUE
((Boolean)true) == Boolean.valueOf(true)
((Integer)1) == Integer.valueOf(1)
I'...
Rabelais asked 16/7, 2015 at 3:44
2
Solved
Usually, treating a struct S as an interface I will trigger autoboxing of the struct, which can have impacts on performance if done often. However, if I write a generic method taking a type paramet...
Proper asked 16/7, 2015 at 14:52
5
Solved
I have a Java class of the following form:
class Example {
private byte[][] data;
public Example(int s) { data = new byte[s][s]; }
public byte getter(int x, int y) { return byte[x][y]; }
pu...
Coley asked 3/4, 2013 at 15:11
3
Solved
The following code compiles (with Java 8):
Integer i1 = 1000;
int i2 = 1000;
boolean compared = (i1 == i2);
But what does it do?
Unbox i1:
boolean compared = (i1.intvalue() == i2);
or box i2...
Forsooth asked 26/5, 2015 at 9:26
1
Solved
I have been studying Decorator pattern and developed simple class ToUpperCaseInputStream. I overrode read() method so it could convert all chars from InputStream to uppercase. Code of the method is...
Baxley asked 17/1, 2015 at 19:6
2
Solved
I am trying to formulate the rules that are being used in the scenarios below. Please explain why I am getting 2 different outputs.
Scenario 1 output: I am an object.
class Test {
public static...
Fallow asked 14/1, 2015 at 10:7
1
Solved
I have a method that returns a Long object datatype via invocation of: resp.getResultCode(). I want to compare it HttpStatus.GONE.value() which actually just returns a primitive int value of 410. W...
Incursive asked 5/11, 2014 at 15:49
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