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Since: Apr./22nd/2004

Java ?ZLeBf

Java?dlx?ZLeBf??A???O??Kw?l?F

1. NX[_[?NX?[hE`FbN
2. JVM??sverifier???`FbN
3. s?ZLeB}l[W^ANZXRg[[?骭�`FbN

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• u[gXgbvNX[_[EEERAEpbP[W rt.jar [h
• gNX[_[EEEjre/lib/ext ?gpbP[WNX[h
• VXeNX[_[EEE??CLASSPATH?B?\?AvP[V?NX?g@\@\[h

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?NX[_[??A?NX ClassLoader p?A\bh findClass() loadClassData() I[o[Ch?BINX[hAe?NX[_?????JX^ENX[_[驍ｱ?l?B

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2. ????e?NX[_?ﾑ、
3. ?s?A findClass() ? "*.class" [hA
4. defineClass() "*.class" ?oCgzioCgR[hjNX\z?B

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JavaTh{bNX?????C???ZLeB}l[W (java.lang.SecurityManager) ?BftHg??A[J?AvP[V??ZLeB}l[WCXg[?A????\?BAAvbg??Ai?ZLeB}l[WCXg[A[J?t@CVXe?ANZXAjAAvbg?[h?O?zXg??驍ｱ?h~??B

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System.setSecurityManager(new SecurityManager());

javas?VXevpeB"java.security.manager"w?驍ｱ??l???F

>java -Djava.security.manager MyAppl

ANZXRg[[

SDK 1.2?~Java2?AZLeB}l[W??o??ANZXRg[[(java.security.AccessController)?B{I????AZLANX[_[`p[^[ZLeB}l[W??AZLeB}l[W?ZLeB[|V????ANZX`FbN髀�ANZXRg[[???B

?ANZXRg[???驍ｱ???B??A"/tmp"????t@C????`FbN???Xg1?R[hg?B

Xg1. ANZX`FbNR[h

try {
	// ??ANZX?IuWFNg??
	FilePermission perm = new FilePermission("/tmp/*", "read, write");
	// ANZXRg[??`FbN
	AccessController.checkPermission(perm);
	...
	// ?
	...
} catch (AccessControlException ex) {
	// ANZX`FbNs?O
	ex.printStackTrace();
}

AvP[V?Ajava.io.FilePermission???ANZX?A|Vt@C???eLXgt@C???驍ｱ???B?A|V[t@C?ANZX??????B

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