- theory: https://github.com/mtumilowicz/java-stack
StackTraceElementclass represents a stack frame- useful methods:
int getLineNumber()String getClassName()String getMethodName()
- useful methods:
- to get all frames of the current thread's stack
- first element of the array is the top frame in the stack (last method invocation)
StackTraceElement[] frames = new Throwable().getStackTrace();StackTraceElement[] frames = Thread.currentThread().getStackTrace();
- drawbacks:
getStrackTrace()returns entire stack - we may need only top 5 elements for example- no easy way to filter
StackTraceElementcontains method names and class names, but we often need class references
- for test purposes
class StackWalking { void m1() { m2(); } private void m2() { m3(); } private void m3() { System.out.println("---"); System.out.println("stack from m3():"); Arrays.stream(new Throwable().getStackTrace()) // getStackTrace on Throwable .forEach(System.out::println); System.out.println("---"); m4(); } private void m4() { System.out.println("---"); System.out.println("stack from m4():"); Arrays.stream(Thread.currentThread().getStackTrace()) // getStackTrace on Thread .forEach(System.out::println); System.out.println("---"); } } - simulation
produces:
@Test public void simulation() { new StackWalking().m1(); }--- stack from m3(): StackWalking.m3(StackWalking.java:18) StackWalking.m2(StackWalking.java:12) StackWalking.m1(StackWalking.java:8) StackWalkingTest.simulation(StackWalkingTest.java:10) ... // other --- --- stack from m4(): java.base/java.lang.Thread.getStackTrace(Thread.java:1606) StackWalking.m4(StackWalking.java:28) StackWalking.m3(StackWalking.java:22) StackWalking.m2(StackWalking.java:12) StackWalking.m1(StackWalking.java:8) StackWalkingTest.simulation(StackWalkingTest.java:10) .. // other ---