So what happens when I add something to the build path of a web-app ? The dependency is not registered ? Also does that mean that whatever dependency I need I will have to put it in the /lib folder ? I just don't understand why it doesn't work if I add it to the Build Path from Eclipse like I do for a normal Java Application.
On Thu, Feb 19, 2015 at 2:19 AM, Christopher Schultz < ch...@christopherschultz.net> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > Sreyan, > > (Sorry, I sent way before I was done writing. Full intentional message > follows.) > > On 2/18/15 10:15 AM, sreya...@gmail.com wrote: > > What is the SYSTEM PATH that you are referring to ? Is it the > > JAVA_HOME or the PATH system variable ? > > Neither of those. It's commonly referred to as the CLASSPATH > environment variable, which should pretty much never be set because > it's horribly confusing. > > Instead, Tomcat uses "java -classpath [the classpath]" to launch the > JVM. The classpath used there includes two JAR files: > > > bin/bootstrap.jar bin/tomcat-juli.jar > > So the only thing that javax.sql.DriverManager can scan is the boot > classpath (that includes all the JVM internals) plus the system > classpath (which includes just those two specific JARs above). > > > What is the CLASSPATH just before Tomcat properly starts up? > > The boot class path includes JVM stuff (rt.jar, etc.) > > The system class path includes anything the JVM environment was > instructed to load when launched (either from the CLASSPATH > environment variable, or from the "-classpath" argument on the > command-line). > > Tomcat's bootstrap class creates a new ClassLoader which includes > everything in lib/*.jar and then starts the Tomcat container using > *that* as the effective "class path". > > > What is it after it starts up? > > Well, Tomcat can see everything in the boot and system class paths > (ClassLoaders) plus everything in lib/*.jar. > > > Correct me if I am wrong that means that whatever dependencies I > > have in my project is not added to the SYSTEM CLASSPATH but is > > instead loaded by TOMCAT. > > Correct. > > > So if a module searches only the SYSTEM CLASSPATH it won’t be able > > to find the dependencies. Am I right ? > > Correct. And DriverManager can't search *down* into ClassLoaders it > doesn't know about -- including Tomcat's ClassLoader. So, > DriverManager can't load your JDBC driver using its standard detection > algorithm. > > So, you still need to call Class.forName to register the driver. > > - -chris > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1 > Comment: GPGTools - http://gpgtools.org > > iQIcBAEBCAAGBQJU5PrwAAoJEBzwKT+lPKRY0/kP/Raf7VLP18ZpzXlLqK+ehPW5 > 1tDiJAG/uiz9L+v3/cOgmqcabHI7m4BSGdd8eeW2G8CYNpjRYDRTjq8dGVPkkzO6 > 4ZR3CX2Hgawxw7Qg8hnDh+Fjq+o7yOclY9T0rQFzcP4UnS4cRnRDRHGZtADycP9Y > Fdgnq5ey/NloTYaUioAmdnL1wnj9pzhRkpzztI8fxhQ1q2AdkLojMUSOArlfg1X5 > N/aSTA0ULhB8Socxiln6TSnjAMxoe2/1PCNwLcIzqLKJcN3zA2rt4eAf5F2JbC50 > zJtfVNa5CEZa3W0Gj5Arl3YWp0rrBa/fNdv7j8iPoF7WZOJbACkZEYuQeS5U3SyS > kyPhKAkE0b5wICzT+H7VUkNCRi0Gb02ER+QFg/UnoYyX91HHJPKSXfPLmD1fraq0 > YkrhmrXp2O7rRa7YiIDp0yL8d7tNppT7sObyzKzZ1TI7Bf5DXEFsx82aXXWQ7wO4 > VOJh14CuaaBhmxWei3w+pUsoLxe359Fmj2cGbAjfCxGUqJhyZgltjMWCvagXM119 > wg645c9nD71hpX1VpHiPQmougHB8a/w1ripd5hVwdT0NRnlYYG1oDKgT83dEYnkk > 7yVnuGSA/upinWjdV+GjWCgLr1Kx8O0B4isX0yqBYXtQXh8m4/jDbFGx0V1mGFXW > aMQS15YHd+kU8oB65ioP > =sv9k > -----END PGP SIGNATURE----- > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > >
