getStackTrace人家才初始化的

public StackTraceElement[] getStackTrace() {
        return (StackTraceElement[]) getOurStackTrace().clone();
    }

    private synchronized StackTraceElement[] getOurStackTrace() {
        // Initialize stack trace if this is the first call to this method
        if (stackTrace == null) {
            int depth = getStackTraceDepth();
            stackTrace = new StackTraceElement[depth];
            for (int i=0; i < depth; i++)
                stackTrace[i] = getStackTraceElement(i);
        }
        return stackTrace;
    }

public static  String getErrorInfoAsString(final Throwable e){
		OutputStream ostr = new ByteArrayOutputStream();
		e.printStackTrace(new PrintStream(ostr));
		return ostr.toString();
	}

public static String getStackTraceCleanVersion(final Throwable e) {
		String str = "";
		if (e == null) 
			return str;
		StackTraceElement[] t = e.getStackTrace();
		
		for (int i = 0; t != null && i < t.length; i++) {
			
			StackTraceElement tem = t[i];
			str += tem.toString() + "\r\n";
		}
		return str;
	}