Java Double getting initialized to 0.0

Question

I have a bean where I have a field "CustAmount "which is double, I tried testing the bean and i dont seem to understand this: When i run on my local machine it gets initialized to 0.0 when instantiated. When i run the same code in my linux test environment it remains null. due to which there is a difference in the retrieved data meaning if i send the CustAmount as null to my Backend i get some data but if i send the CustAmount as 0.0 the query is done on the basis of 0.0 and sends me nothing back.

How is this possible if the code is same, By any chance is it possible that when i do new MyBean() compiled in java 1.5 the double remains null and in 1.6 it gets initialized to 0.0.

I dont know if this is something that happens in two Java versions but thats the only difference on my end.

Thanks for any hint.

Adding code snippet :

public class MyBean { private double custAmount; public void setCustAmount(double custAmount) { this.custAmount = custAmount; } public double getCustAmount() { return custAmount; } }

And I just do

MyBean mybean = new MyBean();

its not a Double but a double. Syed..

This will have nothing to do with Java versions and everything to do with server environment. Presumably this is a web application: are you running the same version of the same server on both machines? — Ernest Friedman-Hill
– Ernest Friedman-Hill, Commented Mar 19, 2012 at 11:14
1) "there is not much code" For better help sooner, post an SSCCE. 2) A CustAmount field should be custAmount. I'm not sure if the exact case is important for beans, but I'd recommend changing it. — Andrew Thompson
– Andrew Thompson, Commented Mar 19, 2012 at 11:18
We need at least a definition of the double field, any setters/getters and how you send/retrieve it. Without any code (ideally a SSCCE) it's hard to help you. As a general rule: the more effort you put into your question the more effort people will put into their answers. — Thomas
– Thomas, Commented Mar 19, 2012 at 11:20

Stephen C · Accepted Answer · 2015-12-11 12:13:20Z

A Java double field will be default initialized to 0.0. A Java Double field will be default initialized to null. These two facts will be true no matter what version of Java you use, and no matter what environment you run it in.

If you are seeing different behavior in different environments, then the most likely explanation is that you are executing DIFFERENT code in the respective environments (or calling the same code in different ways). Posting some code that exhibits the problem may point to some other problem, but I doubt it.

Based on your posted code, it is IMPOSSIBLE for custAmount to be null. In the case where you are seeing a null, you must be EITHER using a different version of that code, OR the null must be coming from some other source.

And, a double cannot be null since it is a primitive. I agree with Stephen, you're probably running different code.
the code was the same. but there was some XSL transformation done and there the double was handled differently and my XSL wasnt updated. So yes in a sense my code was different.

xMichal · Accepted Answer · 2016-12-20 16:49:08Z

I had a similar problem. I thought my Long initializes to 0. But it wasn't initialized itself, but from the <p:selectOneMenu /> on my page.

 <p:selectOneMenu value="#{myBean.myLongValue}"> <f:selectItem value="#{null}" itemValue="#{null}" itemLabel="-" /> <f:selectItems ... /> </p:selectOneMenu>

So, try to check your page, if you are not setting it somehow from your form.

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