How to import a class from default package

Question

Possible Duplicate  How to access java-classes in the default-package      I am using Eclipse 3 5 and I have created a project with some package structure along with the default package  I have one class in default package - Calculations java and I want to make the use of that class in any of the package  for instance in com company calc   When I try to make the use of the class which is in the default package  it s giving me a compiler error  It s not able to recognise the class in default package  Where is the problem   Calculations java - source code  public class Calculations       native public int Calculate int contextId       native public double GetProgress int contextId       static            System loadLibrary  Calc              I can t put my class in any other package  This class has some native methods which are implemented in Delphi  If I put that class in any of the folders  I will have to make changes to that DLL which I want to avoid  really - I can not   That s why I put my class in the default package

User · Answer

Unfortunately  you can t import a class without it being in a package  This is one of the reasons it s highly discouraged  What I would try is a sort of proxy -- put your code into a package which anything can use  but if you really need something in the default package  make that a very simple class which forwards calls to the class with the real code  Or  even simpler  just have it extend   To give an example   import my packaged DefaultClass   public class MyDefaultClass extends DefaultClass     package my packaged DefaultClass   public class DefaultClass          Code here

User · Answer

Create a new package  And then move the classes of default package in new package and use those classes

User · Answer

Classes in the default package cannot be imported by classes in packages  This is why you should not use the default package

User · Answer

I can give you this suggestion  As far as know from my C and C   Programming experience  Once  when I had the same kinda problem  I solved it by changing the dll written structure in   C  File by changing the name of the function which implemented the JNI native functionality   for example  If you would like to add your program in the package  com mypackage   You change the prototype of the JNI implementing   C  File s function method to this one        JNIEXPORT jint JNICALL Java com mypackage Calculations Calculate JNIEnv  env  jobject obj  jint contextId         code goes here    JNIEXPORT jdouble JNICALL Java com mypackage Calculations GetProgress JNIEnv  env  jobject obj  jint contextId        code goes here     Since I am new to delphi  I can not guarantee you but will say this finally   I learned few things after googling about Delphi and JNI   Ask those people  If you are not the one  who provided the Delphi implementation of the native code to change the function names to something like this   function Java com mypackage Calculations Calculate PEnv  PJNIEnv  Obj  JObject  contextId  JInt  JInt    IFDEF WIN32  stdcall    ENDIF    IFDEF LINUX  cdecl    ENDIF  var   Any variables you might be interested in begin     Some code goes here end     function Java com mypackage Calculations GetProgress PEnv  PJNIEnv  Obj  JObject  contextId  JInt  JDouble    IFDEF WIN32  stdcall    ENDIF    IFDEF LINUX  cdecl    ENDIF  var   Any variables you might be interested in begin   Some code goes here end    But  A final advice  Although you  If you are the delphi programmer  or them will change the prototypes of these functions and recompile the dll file  once the dll file is compiled  you will not be able to change the package name of your  Java  file again  amp  again  Because  this will again require you or them to change the prototypes of the functions in delphi with changed prefixes  e g  JAVA yourpackage with underscores for inner packages JavaFileName MethodName   I think this solves the problem  Thanks and regards  Harshal Malshe

User · Answer

Create  root  package  folder  in your project  for example   package source       path to project source   Move YourClass class into a source folder       path to project source YourClass class  Import like this  import source YourClass

User · Answer

From some where I found below  -   In fact  you can   Using reflections API you can access any class so far  At least I was able to     Class fooClass   Class forName  FooBar    Method fooMethod       fooClass getMethod  fooMethod   new Class     String class      String fooReturned        String  fooMethod invoke fooClass newInstance     I did it

User · Answer

Create a new package  Move your files from the default package to the new one

User · Answer

There is a workaround for your problem  You can use reflection to achieve it   First  create an interface for your target class Calculatons    package mypackage   public interface CalculationsInterface         int Calculate int contextId         double GetProgress int contextId          Next  make your target class implements that interface   public class Calculations implements mypackage CalculationsInterface        Override     native public int Calculate int contextId        Override     native public double GetProgress int contextId       static            System loadLibrary  Calc              Finally  use reflection to create an instance of Calculations class and assign it to a variable of type CalculationsInterface    Class lt   gt  calcClass   Class forName  Calculations    CalculationsInterface api    CalculationsInterface calcClass newInstance       Use it  double res   api GetProgress 10

User · Answer

From the Java language spec      It is a compile time error to import a type from the unnamed package    You ll have to access the class via reflection or some other indirect method

[java] How to import a class from default package

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