Behaviour is different when program is exectued from windowsNT and solaris
from /usr/local/java/jdk1.4
java.util.prefs.Preferences getFloat()
While testing on Ultra60/SunOs5.7
Following line is output at the end of the program:
Couldn't flush system prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.

Please see Observation case4:

 Observation:
-----------------------------------------------------------------------------
windowsNT Case 1 :
                             
d:/jdk1.4/bin/java GetFloatTest
   passes

windows NT Case 2:

/usr/local/java/jdk1.4/win/bin/java GetFloatTest
  passes

SunOS 5.7 case 3:

/home/pande/jdk1.4/bin/java GetFloatTest
    passes

SunOS 5.7 case 4:

/usr/local/java/jdk1.4/solsparc/bin/java GetFloatTest
  passes
with following message:

Couldn't flush system prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
 
---------------------------------------------------------

Test Program:
 

import java.util.prefs.*;
import java.util.*;
 
/**
 *
 *GetFloatTest01: Single JVM and Thread case:
 *
 *GetFloatTest01: java.util.prefs.Preferences long getFloat(java.lang.String key, float def)
 *Create userRoot preferences
 *Create "N1" node in userRoot
 *In "N1" put key "k1" and value 1l
 *verify 1l is put by calling getFloat() method, if ok then pass.
 *
 *GetFloatTest02: check for default
 *
 *GetFloatTest03: remove node and see that IllegalStateException is thrown when getFloat() is called.
 *
 *GetFloatTest04: key = null and see that NullPointerException is thrown when getFloat() is called.
 *
 */
public class GetFloatTest {
    
    public static void main(String[] args) throws Exception {
        
        boolean status[];
        int passcount = 0, failcount = 0;
        int numTests = 4;
        int i, j = 0;
    
        status = new boolean[numTests];
        System.out.println("Total tests for Exec : "+numTests);
         
        for(i = 0; i < numTests; ++i) {
// GetFloat all tests in try... catch block
       try {
++j;
switch (j) {
case 1:
status[i] = GetFloatTest01();
break;
case 2:
status[i] = GetFloatTest02();
break;
case 3:
status[i] = GetFloatTest03();
break;
case 4:
status[i] = GetFloatTest04();
break;
}

  } catch (Exception e) {
             status[i] = false;
System.out.println ("Exception in test "+j+": "+e.getMessage());
e.printStackTrace();
            }
        } // end for

        // Get pass and fail totals
        for(i = 0; i < numTests; ++i) {
       if (status[i] == true)
passcount++;
else
failcount++;
        }
    
        System.out.println("Pass count: " + passcount);
        System.out.println("Fail count: " + failcount);

        // check if tests passed
        if ( failcount < 1 ) {
           System.out.println("Test for GetFloat.java Passed");
           System.exit(0);
        } else {
           System.out.println("Test for GetFloat.java Failed");
           System.exit(1);
        }
        
     } // end main
  

/**
 *
 *GetFloatTest01: java.util.prefs.Preferences long getFloat(java.lang.String key, float def)
 *Create userRoot preferences
 *Create "N1" node in userRoot
 *In "N1" put key "k1" and value 1.0f
 *verify 1.0f is put by calling getFloat() method, if ok then pass.
 *
 */
   public static boolean GetFloatTest01() {

boolean bReturn = false;
       try {
           Preferences userRoot = Preferences.userRoot();
           Preferences N1 = userRoot.node("N1");
           N1.clear();
           float float01 = 1.0f;
           N1.putFloat("k1",float01);
           N1.flush();
           float gotFloat = N1.getFloat("k1",0.0f);
           if (gotFloat != 1.0f) {
              throw new Exception("gotFloat != 1.0f not ok in GetFloatTest01()");
           }
           bReturn = true;
           System.out.println("GetFloatTest01() Pass");
       } catch(Exception e) {
           bReturn = false;
           System.out.println("Exception thrown = " + e);
           System.out.println("GetFloatTest01() Fail");
           e.printStackTrace();
       }
       return bReturn;
    }
/**
 *
 *GetFloatTest02: check for default
 */
   public static boolean GetFloatTest02() {

boolean bReturn = false;
       try {
           Preferences userRoot = Preferences.userRoot();
           Preferences N1 = userRoot.node("N1");
           N1.clear();
           float float01 = 1.0f;
           N1.putFloat("k1",float01);
           N1.flush();
           float gotFloat = N1.getFloat("k2",0.0f);
           if (gotFloat != 0.0f) {
              throw new Exception("gotFloat != 0.0f not ok in GetFloatTest02()");
           }
           bReturn = true;
           System.out.println("GetFloatTest02() Pass");
       } catch(Exception e) {
           bReturn = false;
           System.out.println("Exception thrown = " + e);
           System.out.println("GetFloatTest02() Fail");
           e.printStackTrace();
       }
       return bReturn;
    }
  
 
/**
 *
 *GetFloatTest03: remove node and see that IllegalStateException is thrown when getFloat() is called.
 *
 */
   public static boolean GetFloatTest03() {

boolean bReturn = false;
       try {
           Preferences userRoot = Preferences.userRoot();
           Preferences N1 = userRoot.node("N1");
           float float01 = 1.0f;
           N1.putFloat("k1",float01);
           N1.flush();
           N1.removeNode();
           N1.getFloat("k1",0.0f);
           bReturn = false;
           System.out.println("GetFloatTest03() Fail");
      } catch(IllegalStateException ise) {
           bReturn = true;
           System.out.println("Expected IllegalStateException thrown GetFloatTest03()Pass");
      } catch(Exception e) {
           bReturn = false;
           System.out.println("Exception thrown = " + e);
           System.out.println("GetFloatTest03() Fail");
           e.printStackTrace();
       }
       return bReturn;
    }
/**
 *
 *GetFloatTest04: key = null and see that NullPointerException is thrown when getFloat() is called.
 *
 */
   public static boolean GetFloatTest04() {

boolean bReturn = false;
       try {
           Preferences userRoot = Preferences.userRoot();
           Preferences N1 = userRoot.node("N1");
           float float01 = 1.0f;
           N1.putFloat("k1",float01);
           N1.flush();
           N1.removeNode();
           N1.getFloat(null,0.0f);
           bReturn = false;
           System.out.println("GetFloatTest04() Fail");
      } catch(NullPointerException ise) {
           bReturn = true;
           System.out.println("Expected NullPointerException thrown GetFloatTest04()Pass");
      } catch(Exception e) {
           bReturn = false;
           System.out.println("Exception thrown = " + e);
           System.out.println("GetFloatTest04() Fail");
           e.printStackTrace();
       }
       return bReturn;
    }
 }

-----------------------------------------outputresult case 3----
   javasupport2:/home/pande/merlin/dev/testbase/src/libs_api_tests/common/java_util/prefs/Preferences/SJvmSThread/userRoot/GetFloat 32 % /home/pande/merlin/jdk14/bin/java GetFloatTest
Total tests for Exec : 4
GetFloatTest01() Pass
GetFloatTest02() Pass
Expected IllegalStateException thrown GetFloatTest03()Pass
Expected NullPointerException thrown GetFloatTest04()Pass
Pass count: 4
Fail count: 0
Test for GetFloat.java Passed
------------------------------------------case4 output-----------------
/usr/local/java/jdk1.4/solsparc/bin/java GetFloatTest
Total tests for Exec : 4
GetFloatTest01() Pass
GetFloatTest02() Pass
Expected IllegalStateException thrown GetFloatTest03()Pass
Expected NullPointerException thrown GetFloatTest04()Pass
Pass count: 4
Fail count: 0
Test for GetFloat.java Passed
Couldn't flush system prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.