When I tried doing Spike's Hello World class loader example, I came across a Java class method named NewInstance(). This method returns a new instance of the given class instantiated as if it the "new" directive was called with an empty list of constructor parameters. For those of you who use ColdFusion's CreateObject() method, you know that there is some overhead with creating Java objects. I wanted to see if it might be faster to store a class definition and then use NewInstance() than it would be to use CreateObject().
<!--- Get a string buffer class definition. This is the class that will use later with NewInstance(). ---> <cfset objStringBufferClass = CreateObject( "java", "java.lang.StringBuffer" ).GetClass() /> <!--- Set the number of iterations. ---> <cfset intIterations = 1000 /> <!--- Now we want to test the traditional CreateObject methodology where we use ColdFusion to create a new Java object as we need it. ---> <cftimer label="CreateObject Method" type="outline"> <!--- Loop over the number of iterations to test speed. ---> <cfloop index="intI" from="1" to="#intIterations#" step="1"> <!--- Create the string buffer. ---> <cfset objBuffer = CreateObject( "java", "java.lang.StringBuffer" ).Init() /> <!--- Add a random name to the text buffer. ---> <cfset objBuffer.Append( ListGetAt( "Libby,Ashely,Sarah", RandRange( 1, 3 ) ) ) /> </cfloop> </cftimer> <!--- Now, we want to test the Java method NewInstance() as a means to create new Java objects as we need them. ---> <cftimer label="NewInstance Method" type="outline"> <!--- Loop over the number of iterations to test speed. ---> <cfloop index="intI" from="1" to="#intIterations#" step="1"> <!--- Create the string buffer using the NewInstance method called on our stored StringBuffer class definition. ---> <cfset objBuffer = objStringBufferClass.NewInstance() /> <!--- Add a random name to the text buffer. ---> <cfset objBuffer.Append( ListGetAt( "Libby,Ashely,Sarah", RandRange( 1, 3 ) ) ) /> </cfloop> </cftimer>
The results were not very interesting. There was no huge performance gain. There's wasn't even any consistency. In small cases, such as 1,000 iterations, the NewInstance() method was faster than the CreateObject() method... but only by milliseconds. However, when we pumped the test case up to around 10,000 iterations, the CreateObject() method was consistently faster. Not sure that is all about.
So, while it may have been a neat thought, it seems that NewInstance() holds no advantage in any general Java class instantiation case. Plus, you can't pass in constructor arguments with it. Well, at least not with this version... it looks like in Java there is some sort of reflect Constructor class that has a NewInstance() method that can take arguments... but I don't feel like it's worth looking into at this point.
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Thanks a lot Ben.It help me a lot for creating my first java object.
No problem. CreateObject() is a great and easy way to create Java objects. There's a whole world of power to be leveraged just below the surface of ColdFusion.
There might be 2 things making that the test results are not faster for newInstance:
- the newInstance method is called on a java proxy. Which might wrap the new instance anyway, just like createobject.
- The random name adding could be slower then creating objects, therefore it could mask the speed differences between createobject and newinstance.