JDK class loading source code

 

 

 

Public class launcher {
Static class appclassloader extends urlclassloader {

Public static classloader getappclassloader (classloader)
Throws ioexception {
String S = system. getproperty ("Java. Class. Path ");
File afile [] = s! = NULL? Launcher. getclasspath (s): new file [0];
Return (appclassloader) accesscontroller
. Doprivileged (New privilegedaction (S, afile, classloader ){

Public object run (){
URL aurl [] = s! = NULL? Launcher. pathtourls (PATH)
: New URL [0];
Return new appclassloader (aurl, extcl );
}

Final string Val $ S;

Final file Val $ path [];

Final classloader Val $ extcl;

{
S = S1;
Path = afile;
Extcl = classloader;
Super ();
}
});
}

Public synchronized class loadclass (string S, Boolean flag)
Throws classnotfoundexception {
Int I = S. lastindexof ('.');
If (I! =-1 ){
Securitymanager = system. getsecuritymanager ();
If (securitymanager! = NULL)
Securitymanager. checkpackageaccess (S. substring (0, I ));
}
Return super. loadclass (S, flag );
}

Protected permissioncollection getpermissions (codesource ){
Permissioncollection = super
. Getpermissions (codesource );
Permissioncollection. Add (New runtimepermission ("exitvm "));
Return permissioncollection;
}

Private Static accesscontrolcontext getcontext (File afile [])
Throws malformedurlexception {
Pathpermissions = new pathpermissions (afile );
Protectiondomain = new protectiondomain (
New codesource (pathpermissions. getcodebase (),
(Java. Security. cert. Certificate []) null ),
Pathpermissions );
Accesscontrolcontext = new accesscontrolcontext (
New protectiondomain [] {protectiondomain });
Return accesscontrolcontext;
}

Appclassloader (URL aurl [], classloader ){
Super (aurl, classloader, launcher. Factory );
}
}

Static class extclassloader extends urlclassloader {

Public static extclassloader getextclassloader ()
Throws ioexception
{
File afile [] = getextdirs ();
Try
{
Return (extclassloader) accesscontroller. doprivileged (New privilegedexceptionaction (afile ){

Public object run ()
Throws ioexception
{
Return new extclassloader (dirs );
}

Final file Val $ dirs [];

Throws ioexception
{
Dirs = afile;
Super ();
}
}
);
}
Catch (privilegedactionexception)
{
Throw (ioexception) privilegedactionexception. getexception ();
}
}

Void addexturl (URL ){
Super. addurl (URL );
}

Private Static file [] getextdirs (){
String S = system. getproperty ("Java. Ext. dirs ");
File afile [];
If (s! = NULL ){
Stringtokenizer = new stringtokenizer (S,
File. pathseparator );
Int I = stringtokenizer. counttokens ();
Afile = new file [I];
For (Int J = 0; j <I; j ++)
Afile [J] = new file (stringtokenizer. nexttoken ());

} Else {
Afile = new file [0];
}
Return afile;
}

Private Static URL [] getexturls (File afile []) throws ioexception {
Vector vector = new vector ();
For (INT I = 0; I <afile. length; I ++ ){
String as [] = afile [I]. List ();
If (as = NULL)
Continue;
For (Int J = 0; j <as. length; j ++ ){
File file = new file (afile [I], as [J]);
Vector. Add (launcher. getfileurl (File ));
}

}

URL aurl [] = new URL [vector. Size ()];
Vector. copyinto (aurl );
Return aurl;
}

Public String findlibrary (string s ){
S = system. maplibraryname (s );
For (INT I = 0; I <dirs. length; I ++ ){
String S1 = system. getproperty ("OS. Arch ");
If (S1! = NULL ){
File file = new file (dirs [I], S1), S );
If (file. exists ())
Return file. getabsolutepath ();
}
File file1 = new file (dirs [I], S );
If (file1.exists ())
Return file1.getabsolutepath ();
}

Return NULL;
}

Private Static accesscontrolcontext getcontext (File afile [])
Throws ioexception {
Pathpermissions = new pathpermissions (afile );
Protectiondomain = new protectiondomain (
New codesource (pathpermissions. getcodebase (),
(Java. Security. cert. Certificate []) null ),
Pathpermissions );
Accesscontrolcontext = new accesscontrolcontext (
New protectiondomain [] {protectiondomain });
Return accesscontrolcontext;
}

Private file dirs [];

Public extclassloader (File afile []) throws ioexception {
Super (getexturls (afile), null, launcher. Factory );
Dirs = afile;
}
}

Private Static class factory implements urlstreamhandlerfactory {

Public urlstreamhandler createurlstreamhandler (string s ){
String S1 = (New stringbuilder (). append (prefix). append (".")
. Append (s). append (". Handler"). tostring ();
Try {
Class class1 = Class. forname (S1 );
Return (urlstreamhandler) class1.newinstance ();
} Catch (classnotfoundexception ){
Classnotfoundexception. printstacktrace ();
} Catch (instantiationexception ){
Instantiationexception. printstacktrace ();
} Catch (illegalaccessexception ){
Illegalaccessexception. printstacktrace ();
}
Throw new internalerror (New stringbuilder (). append (
"Cocould not load"). append (s). append (
"System protocol handler"). tostring ());
}

Private Static string prefix = "sun.net. www. Protocol ";

Private Factory (){
}

}

Public static launcher getlauncher (){
Return launcher;
}

Public launcher (){
Extclassloader;
Try {
Extclassloader = extclassloader. getextclassloader ();
} Catch (ioexception ){
Throw new internalerror ("cocould not create extension class loader ");
}
Try {
Loader = appclassloader. getappclassloader (extclassloader );
} Catch (ioexception ioexception1 ){
Throw new internalerror ("cocould not create application Class Loader ");
}
Thread. currentthread (). setcontextclassloader (loader );
String S = system. getproperty ("Java. Security. Manager ");
If (s! = NULL ){
Securitymanager = NULL;
If ("". Equals (s) | "default". Equals (s ))
Securitymanager = new securitymanager ();
Else
Try {
Securitymanager = (securitymanager) loader. loadclass (s)
. Newinstance ();
} Catch (illegalaccessexception ){
} Catch (instantiationexception ){
} Catch (classnotfoundexception ){
} Catch (classcastexception ){
}
If (securitymanager! = NULL)
System. setsecuritymanager (securitymanager );
Else
Throw new internalerror (New stringbuilder (). append (
"Cocould not create securitymanager:"). append (s)
. Tostring ());
}
}

Public classloader getclassloader (){
Return loader;
}

Public static urlclasspath getbootstrapclasspath (){
String S = (string) accesscontroller
. Doprivileged (New getpropertyaction ("Sun. boot. Class. Path "));
URL aurl [];
If (s! = NULL ){
String S1 = s;
Aurl = (URL []) (URL []) accesscontroller
. Doprivileged (New privilegedaction (S1 ){

Public object run (){
Return launcher. pathtourls (Launcher
. Getclasspath (PATH ));
}

Final string Val $ path;

{
Path = s;
Super ();
}
});
} Else {
Aurl = new URL [0];
}
Return new urlclasspath (aurl, factory );
}

Private Static URL [] pathtourls (File afile []) {
URL aurl [] = new URL [afile. Length];
For (INT I = 0; I <afile. length; I ++)
Aurl [I] = getfileurl (afile [I]);

Return aurl;
}

Private Static file [] getclasspath (string s ){
File afile [];
If (s! = NULL ){
Int I = 0;
Int J = 1;
Boolean flag = false;
Int K;
For (INT I1 = 0; (k = S. indexof (file. pathseparator, i1 ))! =-1; I1 = k + 1)
J ++;

Afile = new file [J];
Int L;
Int J1;
For (J1 = L = 0; (L = S. indexof (file. pathseparator, J1 ))! =-1; J1 = L + 1)
If (L-J1> 0)
Afile [I ++] = new file (s. substring (J1, L ));
Else
Afile [I ++] = new file (".");

If (J1 <S. Length ())
Afile [I ++] = new file (s. substring (J1 ));
Else
Afile [I ++] = new file (".");
If (I! = J ){
File afile1 [] = new file [I];
System. arraycopy (afile, 0, afile1, 0, I );
Afile = afile1;
}
} Else {
Afile = new file [0];
}
Return afile;
}

Static URL getfileurl (File file ){
Try {
File = file. getcanonicalfile ();
} Catch (ioexception ){
}
Try {
Return parseutil. filetoencodedurl (File );
} Catch (malformedurlexception ){
Throw new internalerror ();
}
}

Private Static urlstreamhandlerfactory factory = new factory ();

Private Static launcher = new launcher ();

Private classloader loader;

Private Static urlstreamhandler filehandler;

}