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compilation error

Rajat Sarkar
Greenhorn

Joined: Sep 07, 2008
Posts: 18
import java.util.*;

class V2Radiator
{
V2Radiator(ArrayList list)
{
for(int x=0;x<5;x++)
list.add(new SimUnit("V2Radiator"));
}
}

class V3Radiator extends V2Radiator
{
V3Radiator(ArrayList list)
{
super(list);
for(int x=0;x<10;x++)
list.add(new SimUnit("V3Radiator"));
}
}

class RetentionBot
{
RetentionBot(ArrayList list)
{
list.add(new SimUnit("Retention"));
}
}

public class TestLifeSupportSim
{
public static void main(String[] args)
{
ArrayList aList = new ArrayList();
V2Radiator v2 = new V2Radiator(aList);
V3Radiator v3 = new V3Radiator(aList);
for(int z=0; z<20 ; z++)
{
RetentionBot ret = new RetentionBot(aList);
}
}
}

class SimUnit
{
String botType;

SimUnit(String type)
{
botType=type;
System.out.println(type);
}

int powerUse()
{
if("Retetention".equals(botType))
{
return 2;
}
else
{
return 4;
}
}
}

whenever i try to compile this, some type of compilation error comes.it tells

"Note: TestLifeSupportSim.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details. "

what does it mean by that?
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 39869
    
  28
That's not an error; it's a warning that your code might not be type-safe. I haven't got the time to look up the details, but you will probably find something useful in the Java Tutorials: try this section.
Mehar Simhadri
Greenhorn

Joined: Jan 25, 2009
Posts: 4
looks like you dont have type parameters for Arraylist, it will lead to a warning in java 5
Rob Spoor
Sheriff

Joined: Oct 27, 2005
Posts: 19762
    
  20

Mehar,

Please read your private messages regarding an important announcement.

Thank you,

Rob


SCJP 1.4 - SCJP 6 - SCWCD 5 - OCEEJBD 6
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Rajat Sarkar
Greenhorn

Joined: Sep 07, 2008
Posts: 18
Mehar Simhadri wrote:looks like you dont have type parameters for Arraylist, it will lead to a warning in java 5


in that case , ArrayList list =new ArrayList(); & ArrayList<Object> list = new ArrayList<Object>(); is both statement works same.
Rob Spoor
Sheriff

Joined: Oct 27, 2005
Posts: 19762
    
  20

ArrayList<SimUnit> seems to be a better match. That way you won't have to cast the contents when you retrieve them.
 
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subject: compilation error