oop - Can a Java constructor return already existing object of same type? -

-

whenever call constructor in java, creates new object , returns reference in end (of newly created object).

is there possibility java constructor not create new object return reference created object?

// possible myobject not new object, existing object myclass myobject = new myclass();

i have list of objects of class, , based on few parameters in constructor more efficient don't create new object, instead pick existing object. there other way?

no. constructors definition run when new object created initialize it. if constructor run, new object has come existence, , there's nothing can it.

what make static method either creates new object, or returns existing one. standard approach in such cases.

say, boolean.valueof(boolean value) in standard library exists purpose of avoiding creation of objects. can create them using new boolean(value), better call method because return same object same values.


Comments

Post a Comment

Popular posts from this blog

c++ - llvm function pass ReplaceInstWithInst malloc -

-
#include "llvm/pass.h" #include "llvm/ir/module.h" #include "llvm/ir/function.h" #include "llvm/support/raw_ostream.h" #include "llvm/ir/legacypassmanager.h" #include "llvm/ir/instrtypes.h" #include "llvm/transforms/ipo/passmanagerbuilder.h" #include "llvm/ir/irbuilder.h" #include "llvm/transforms/utils/basicblockutils.h" using namespace llvm; namespace { struct replacepass : public functionpass { static char id; replacepass() : functionpass(id) {} virtual bool runonfunction(function &f) { allocainst* insttoreplace = ??? basicblock::iterator ii(insttoreplace); replaceinstwithinst(insttoreplace->getparent()->getinstlist(), ii, new allocainst(type::int32ty, 0, insttoreplace)); return true; } }; } char replacepass::id = 0; static void registerreplacepass(const passmanagerbuilder &, legacy::passmanagerbase &pm) { pm.add(new re
Read more

java.lang.NoClassDefFoundError When Creating New Android Project -

-
i've tried installing (and re-installing) android studio several times now, , each time, studio isn't able create new android project. when attempt initial android studio window (ie. basic 'create', 'open', 'import' etc options), i'm asked of questions in wizard, brief progress dialog, followed nothing @ all. if open incomplete project process creates choosing 'open' list, can try choosing create new android project menu. this has same issue, error message in output console time... java.lang.noclassdeffounderror: com/sun/xml/internal/bind/v2/model/annotation/annotationreader (wrong name: com/sun/xml/internal/bind/v0/model/qnnotation/annotationreader) note: when installed android studio, installed incompatible jdk (1.8, not 1.7). have had go default project settings change jdk uses 1.8. does know how can avoid this? there place should downloading jxb classes? missing in java paths? this appears have been caused cor
Read more

Decoding a Python 2 `tempfile` with python-future -

-
i'm attempting write python 2/3 compatible routine fetch csv file, decode latin_1 unicode , feed csv.dictreader in robust, scalable manner. for python 2/3 support, i'm using python-future including imporing open builtins , , importing unicode_literals consistent behaviour i'm hoping handle exceptionally large files spilling disk, using tempfile.spooledtemporaryfile i'm using io.textiowrapper handle decoding latin_1 encoding before feeding dictreader this works fine under python 3. the problem textiowrapper expects wrap stream conforms bufferediobase . unfortunately under python 2, although have imported python 3-style open , vanilla python 2 tempfile.spooledtemporaryfile still of course returns python 2 cstringio.stringo , instead of python 3 io.bytesio required textiowrapper . i can think of these possible approaches: wrap python 2 cstringio.stringo python 3-style io.bytesio . i'm not sure how approach - need write such wrapper or 1 ex
Read more