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Groups > comp.lang.java.programmer > #5205
| From | Abu Yahya <abu_yahya@invalid.com> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Class.forName().newInstance() vs new |
| Date | 2011-06-11 22:43 +0530 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <it07on$ilc$1@speranza.aioe.org> (permalink) |
I have a class that instantiates a private member based on a value in a
configuration file.
The value is used to determine the class name.
I initially decided to use code similar to the following:
// class name comes from property file
String dbMgrClassName = props.getProperty("db.manager");
Class<?> k = Class.forName(dbMgrClassName);
db = (DB) k.newInstance();
db.init(props);
However, a colleague pointed out that using "new" is faster than using
"Class.forName().newInstance()". So, I changed the code to the following:
String dbMgrClassName = props.getProperty("db.manager");
if (dbMgrClassName.equals("DB2"))
db = new DB2();
else if (dbMgrClassName.equals("Oracle"))
db = new Oracle();
else if (dbMgrClassName.equals("SQLServer"))
db = new SQLServer();
else { // handle unrecognized
Class<?> k = Class.forName(dbMgrClassName);
db = (DB) k.newInstance();
}
db.init(props);
My question is: Does using if-else statements like the above really
improve performance? What is the best approach to instantiate classes
whose type you don't know at compile time?
Back to comp.lang.java.programmer | Previous | Next — Next in thread | Find similar
Class.forName().newInstance() vs new Abu Yahya <abu_yahya@invalid.com> - 2011-06-11 22:43 +0530
Re: Class.forName().newInstance() vs new David Lamb <dalamb@cs.queensu.ca> - 2011-06-11 13:46 -0400
Re: Class.forName().newInstance() vs new Robert Klemme <shortcutter@googlemail.com> - 2011-06-11 19:49 +0200
Re: Class.forName().newInstance() vs new Patricia Shanahan <pats@acm.org> - 2011-06-11 11:04 -0700
Re: Class.forName().newInstance() vs new Abu Yahya <abu_yahya@invalid.com> - 2011-06-11 23:52 +0530
Re: Class.forName().newInstance() vs new Robert Klemme <shortcutter@googlemail.com> - 2011-06-12 14:05 +0200
Re: Class.forName().newInstance() vs new Patricia Shanahan <pats@acm.org> - 2011-06-12 07:10 -0700
Re: Class.forName().newInstance() vs new Martin Gregorie <martin@address-in-sig.invalid> - 2011-06-12 14:37 +0000
Re: Class.forName().newInstance() vs new Robert Klemme <shortcutter@googlemail.com> - 2011-06-12 18:17 +0200
Re: Class.forName().newInstance() vs new Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-06-12 15:25 -0400
Re: Class.forName().newInstance() vs new lewbloch <lewbloch@gmail.com> - 2011-06-15 06:58 -0700
Re: Class.forName().newInstance() vs new Nigel Wade <nmw-news@ion.le.ac.uk> - 2011-06-16 10:16 +0100
Re: Class.forName().newInstance() vs new Robert Klemme <shortcutter@googlemail.com> - 2011-06-12 18:10 +0200
Re: Class.forName().newInstance() vs new Abu Yahya <abu_yahya@invalid.com> - 2011-06-11 23:53 +0530
Re: Class.forName().newInstance() vs new "John B. Matthews" <nospam@nospam.invalid> - 2011-06-11 15:43 -0400
Re: Class.forName().newInstance() vs new "John B. Matthews" <nospam@nospam.invalid> - 2011-06-11 15:50 -0400
Re: Class.forName().newInstance() vs new lewbloch <lewbloch@gmail.com> - 2011-06-15 06:49 -0700
Re: Class.forName().newInstance() vs new Michael Wojcik <mwojcik@newsguy.com> - 2011-06-16 11:21 -0400
Re: Class.forName().newInstance() vs new lewbloch <lewbloch@gmail.com> - 2011-06-17 06:45 -0700
Re: Class.forName().newInstance() vs new Michael Wojcik <mwojcik@newsguy.com> - 2011-06-17 12:29 -0400
Re: Class.forName().newInstance() vs new Lewis Bloch <lewisbloch@google.com> - 2011-06-17 11:07 -0700
Re: Class.forName().newInstance() vs new "John B. Matthews" <nospam@nospam.invalid> - 2011-06-18 02:01 -0400
Re: Class.forName().newInstance() vs new Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-18 10:19 -0300
Re: Class.forName().newInstance() vs new Robert Klemme <shortcutter@googlemail.com> - 2011-06-18 20:16 +0200
OT language stuff (was Re: Class.forName().newInstance() vs new) blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-06-20 19:19 +0000
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) Martin Gregorie <martin@address-in-sig.invalid> - 2011-06-20 20:46 +0000
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-06-21 20:42 +0000
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) Gene Wirchenko <genew@ocis.net> - 2011-06-21 14:22 -0700
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-20 18:55 -0300
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) Tom Anderson <twic@urchin.earth.li> - 2011-06-21 23:29 +0100
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-21 20:39 -0300
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) "John B. Matthews" <nospam@nospam.invalid> - 2011-06-21 23:00 -0400
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) Tom Anderson <twic@urchin.earth.li> - 2011-06-22 20:02 +0100
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-06-22 20:03 +0000
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) Michael Wojcik <mwojcik@newsguy.com> - 2011-06-23 12:04 -0400
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) Michael Wojcik <mwojcik@newsguy.com> - 2011-06-23 11:58 -0400
Re: Class.forName().newInstance() vs new Gene Wirchenko <genew@ocis.net> - 2011-06-20 14:01 -0700
Re: Class.forName().newInstance() vs new Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-20 18:53 -0300
Re: Class.forName().newInstance() vs new Michael Wojcik <mwojcik@newsguy.com> - 2011-06-21 19:53 -0400
Re: Class.forName().newInstance() vs new blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-06-22 20:01 +0000
Re: Class.forName().newInstance() vs new Michael Wojcik <mwojcik@newsguy.com> - 2011-06-23 12:16 -0400
OT language stuff (was Re: Class.forName().newInstance() vs new) blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-06-20 19:18 +0000
Re: OT language stuff (was Re: Class.forName().newInstance() vs new) Martin Gregorie <martin@address-in-sig.invalid> - 2011-06-20 20:52 +0000
Re: Class.forName().newInstance() vs new Robert Klemme <shortcutter@googlemail.com> - 2011-06-12 14:14 +0200
Re: Class.forName().newInstance() vs new Patricia Shanahan <pats@acm.org> - 2011-06-11 11:01 -0700
Re: Class.forName().newInstance() vs new Roedy Green <see_website@mindprod.com.invalid> - 2011-06-13 06:16 -0700
Re: Class.forName().newInstance() vs new Ian Shef <invalid@avoiding.spam> - 2011-06-14 20:07 +0000
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