Re: Difference between java object and java string

On 2017-02-08 5:13 PM, Don Brown wrote:

What from an ILE RPG perspective is the difference between the following
variable's ?

D stringJ S O Class(*JAVA : 'java.lang.String')
D objectJ S O Class(*JAVA : 'java.lang.Object')

From RPG's point of view, there is no difference. They are both Java objects. RPG doesn't care about the class of Object _variables_. The only time it is important for RPG to have the correct class is in prototypes.

From Java's point of view, every class in Java is a subclass of the Object class, so a String is also an Object, but an Object isn't necessarily a String.

I have a requirement to pass a java.lang.Object to a procedure.

Sometimes when a method is defined to take an Object, it can actually only handle some specific classes. I suspect that is the case here for your getMap method.

To create a java string I use the makeString procedure.

I can't seem to find a makeObject procedure.

I don't think you want to create a base Object. The Java Map is a map of objects, but usually (always?) of a specific class. You need to create an object of whatever class your specific Map is using.

This is the procedure I want to use ...

D getMap PR O CLASS(*JAVA : 'java.lang.Object' )
D EXTPROC(*JAVA : 'java.util.Map' :
D 'get' )
D arg0 O CLASS(*JAVA : 'java.lang.Object' )

You can pass a String object (or an object of any class) to this method.

The parameter I need to pass is the name of a custom field that is
returned in the transaction object so I am doing the following ...

customJ = makestring('test_custom_key_1');
stringJ = getMap( JavaMap : customJ );

When the program executes the getMap java blows up and generates a core
dump.

Probably a silly question, but does your JavaMap variable have a non-null value?