How to Increase the Number of Displayed Lines of a Java Stack Trace Dump

How do I increase the number of displayed lines of a Java stack trace dump?

You don't need to; that information is present elsewhere in the stack trace. From the docs of printStackTrace():

Note the presence of lines containing the characters "...". These lines indicate that the remainder of the stack trace for this exception matches the indicated number of frames from the bottom of the stack trace of the exception that was caused by this exception (the "enclosing" exception).
This shorthand can greatly reduce the length of the output in the common case where a wrapped exception is thrown from same method as the "causative exception" is caught.

In other words, the "... x more" only appears on a chained exception, and only when the last x lines of the stack trace are already present as part of another chained exception's stack trace.

Suppose that a method catches exception Foo, wraps it in exception Bar, and throws Bar. Then Foo's stack trace will be shortened. If you for some reason want the full trace, all you need to do is take the last line before the ... in Foo's stack trace and look for it in the Bar's stack trace; everything below that line is exactly what would have been printed in Foo's stack trace.

How can I get the current stack trace in Java?

You can use Thread.currentThread().getStackTrace().

That returns an array of StackTraceElements that represent the current stack trace of a program.

Fetch only first N lines of a Stack Trace

I'm assuming from what you are asking, that you don't have an exception to deal with. In which case you can get the current stack trace from:

StackTraceElement[] elements = Thread.currentThread().getStackTrace()

This will tell you pretty much everything you need to know about where you've come from in the code.

How to read the full stacktrace in Java where it says e.g. ... 23 more

The answer is simple, those lines are already in the stacktrace :)

 at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
 at com.azurian.lce.usuarios.ConnectionManager.getConnection(ConnectionManager.java:65)
 at com.azurian.lce.usuarios.db2.UsuarioDAOImpl.autenticar(UsuarioDAOImpl.java:101)
 at com.azurian.lce.usuarios.UsuarioServiceImpl.autenticar(UsuarioServiceImpl.java:31)
 at com.azurian.lce.web.admin.actions.LoginAction.execute(LoginAction.java:49)
 at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
 at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
 at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
 at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
 at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
 at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
 at java.lang.Thread.run(Unknown Source)

Basically, the following is happening in BasicDataSource#createDataSource():

try {
    Class.forName(driverClassName); // Line 1130
} catch (ClassNotFoundException e) {
    throw new SQLNestedException(e, "Cannot load JDBC driver class '" + driverClassName + "'"); // Line 1136
}

How do I get stacktrace of a particular line of Java program

In the end, you are asking for some sort of instrumentation. In other words: you want to tell the jvm to keep track of the call stack and more importantly, make that information available to you programmatically.

And even when you only want that to happen for specific methods, the jvm still has to track all method invocations, as it can't know whether one of the methods to track is called in the end. Thus there is no way of tracking method invocations easily without performance impacts. And the tools I know that can keep that performance impact on a reasonable level, like XRebel are for later evaluation, not for programmatic consumption.

In other words: the only solutions to hang situations are:

doing a thread dump and analyzing it
doing extensive logging/tracing while your code is running, to analyze that in case or hangs

Just to be clear: what you are asking for, to get a stack trace of already executed code after the fact is impossible to achieve!

how to expand size of Java stack trace to see bottom of stack? (triggering a stack overflow)

Try the -XX:MaxJavaStackTraceDepth JVM option.

Here is a description from Stas's Blog

Max. no. of lines in the stack trace for Java exceptions (0 means all).
With Java > 1.6, value 0 really means 0. value -1 or any negative number must be specified to print all the stack (tested with 1.6.0_22, 1.7.0 on Windows).
With Java <= 1.5, value 0 means everything, JVM chokes on negative number (tested with 1.5.0_22 on Windows).