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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6. import java.util.ArrayList;
  7. import java.util.List;
  8. import java.util.Objects;
  9.  
  10. /* Name of the class has to be "Main" only if the class is public. */
  11. class Ideone
  12. {
  13. 	public static void main (String[] args) throws java.lang.Exception
  14. 	{
  15. 		List<Integer> ints = new ArrayList<Integer>(); 
  16. 		List<Double> doubles = new ArrayList<Double>(); 
  17. 		check(null);
  18. 		check(ints);
  19. 		ints.add(1);
  20. 		check(ints);
  21. 		doubles.add(1D);
  22. 		check(doubles);
  23. 	}
  24.  
  25. 	public static void check(List<?> list) {
  26. 		if (Objects.equals(null, list)) 
  27. 			System.out.println("null");
  28. 		else if (list.isEmpty())
  29. 			System.out.println("empty");
  30. 		else if (list.get(0) instanceof Integer)
  31. 			System.out.println("int");
  32. 		else if (list.get(0) instanceof Double)
  33. 			System.out.println("double");
  34. 	}
  35. }
Success #stdin #stdout 0.1s 320512KB
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stdin
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Standard input is empty
stdout
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null
empty
int
double
https://ideone.com/hA3tSc
language:
Java (HotSpot 12)
created:
9 years ago
visibility:
public

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