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Java Enterprise in a Nutshell, Second Edition by David Flanagan, Jim Farley, William Crawford

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Basic Data Types

IDL supports the basic data types shown in Table 14-2. The table also shows the Java type that each is mapped to according to the standard IDL Java mapping. Note that there isn’t a standard mapping defined for the long double IDL type, because Java doesn’t have a basic data type that supports the precision required. Another important thing to note is that Java doesn’t support unsigned types, such as unsigned short. So you’ll see in the table that IDL short and unsigned short are both mapped to the Java short data type. You should be aware of this when writing implementations of IDL-generated Java interfaces, since it is up to you to either ensure that their values remain positive or deal with the fact that their values may in fact be set to negative values.

Table 14-2. IDL Basic Data Types, Sizes, and Java Mappings

IDL Type Specifier

Required Size

Java Data Type

short

16 bits

short
long

32 bits

int
long long

64 bits

long
unsigned short

16 bits

short
unsigned long

32 bits

int
unsigned long long

64 bits

long
char

8 bits

char
wchar

Implementation-dependent

char
string

Unlimited

java.lang.String
string<size>

size chars

java.lang.String
wstring

unlimited

java.lang.String
wstring<size>

size wchars

java.lang.String
boolean

Implementation-dependent

boolean
octet

8 bits

byte
Any

Implementation-dependent

org.omg.CORBA.Any
float

IEEE single-precision

float
double

IEEE double-precision

double
long double

IEEE double-extended ...

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