TC should be the right-hand operand in Java 8 Language Specification -

-

if @ java 8 language specification §15.26.1

  • otherwise, value of index subexpression used select component of array referred value of array reference subexpression.

this component variable; call type sc. also, let tc type of left-hand operand of assignment operator determined @ compile time. there 2 possibilities:

  • if tc primitive type, sc same tc.

the value of right-hand operand converted type of selected array component, subjected value set conversion (§5.1.13) appropriate standard value set (not extended-exponent value set), , result of conversion stored array component.

  1. it says "let tc type of left-hand operand of assignment operator", tc left operand , sc component of array , type of right operand.

so, code goes this:

int tc = 15;
int[] sc = {1,2,3,4,5};
tc = sc[0];

  1. next weird things, says "the value of right-hand operand converted type of selected array component"

execution 1: value of of right-hand operand sc[0] 1.
execution 2: 1 converted type of selected array component sc[0].
execution 3: 1 converted int.

  1. "and result of conversion stored array component"

execution 4: 1 stored in sc[0].

if follow step, code:

tc = sc[0];

is never happened, because sc[0] stored itself.

it should says :

  • otherwise, value of index subexpression used select component of array referred value of array reference subexpression.

this component variable; call type sc. also, let tc type of right-hand operand of assignment operator determined @ compile time. there 2 possibilities:

  • if tc primitive type, sc same tc.

the value of right-hand operand converted type of selected array component, subjected value set conversion (§5.1.13) appropriate standard value set (not extended-exponent value set), , result of conversion stored array component.

so code this:

int tc = 15;
int[] sc = {1,2,3,4,5};
sc[0] = tc;

would run, , value of tc stored sc[0]

my question: right?

it seems have misread context section of jls.

the section quoting starts with

if left-hand operand array access expression (§15.10.3), possibly enclosed in 1 or more pairs of parentheses

the array on left hand side, in

t[0] = 1;

i'm not sure why think implies otherwise, , explicitly dealing assignment array elements.

the particular problem clause addressing is:

interface tc {};  class sc implements tc {};  class rc implements tc {};  tc[] tcarray = new sc[1]; tcarray[0] = new rc();

that code (ignoring syntax shortcuts) compiles, required fail @ runtime arraystoreexception.


Comments

Post a Comment

Popular posts from this blog

c - How to retrieve a variable from the Apache configuration inside the module? -

-
i'm building custom apache module. how retrieve variable apache configuration inside module? see variable "some_var_config_from_apache_or_htaacess" inside apache module: /* source: http://people.apache.org/~humbedooh/mods/examples/mod_example_1.c */ /* include required headers httpd */ #include "httpd.h" #include "http_core.h" #include "http_protocol.h" #include "http_request.h" static void register_hooks(apr_pool_t *pool); static int example_handler(request_rec *r); /* define our module entity , assign function registering hooks */ module ap_module_declare_data example_module = { standard20_module_stuff, null, // per-directory configuration handler null, // merge handler per-directory configurations null, // per-server configuration handler null, // merge handler per-server configurations null, // directives may have httpd register_hoo
Read more

c# - Constructor arguments cannot be passed for interface mocks -

-
when debug code , read line mocklessonplannerafactory creation error: constructor arguments cannot passed interface mocks. var mockschoolclasscodeservice = new mock<ischoolclasscodeservice>(); var mockdateservice = new mock<idateservice>(); var mocklessonplannerafactory = new mock<ilessonplannerafactory>(mockdateservice.object); var mocklessonplannerbfactory = new mock<ilessonplannerbfactory>(mockdateservice.object); var service = new timetableservice(mockunitofwork.object, mocklessonplannerafactory.object, mocklessonplannerbfactory.object, mockschoolclasscodeservice.object); my timetableservice accepts instances of interface type only. mocklessonplannerafactory , bfactory... want in constructor idateservice passed. what wrong code? the clue in error message "constructor arguments cannot passed interface mocks." the mock created interface have default constructor because interfaces don't have constructor. remember mockin
Read more

python - malformed header from script index.py Bad header -

-
i want run python code in apache2(ubuntu 14.04) server. have followed these steps , getting error: step 1: configuration 1: have created directory , file under /var/www/cgi-bin configuration 2 : have edited /etc/apache2/sites-available/000-default.conf alias /cgi-bin /var/www/cgi-bin <directory "/var/www/cgi-bin"> options indexes followsymlinks execcgi addhandler cgi-script .cgi .py allow </directory> <directory /var/www/cgi-bin> options </directory> step 2: and python script is: index.py #!/usr/bin/env python import cgi; import cgitb;cgitb.enable() print "content-type: text/plain\n" print "<b>hello python</b>" step 3: when ran through chrome browser using: url : http://localhost/cgi-bin/index.py step 4: i getting error in error-log malformed header script 'index.py': bad header: hello python you should end header \r\n, must print out yet \r\n signal body coming. (i
Read more