java.lang.IllegalStateException: Imbalanced frame stack! (exit() called too many times) !

If you started using SpringSource Insight,It's highly recommended to increase the memory of the tc Runtime Instance to more than what your application requires on its own . The following is the exception you might see in case there is not enough memory.
type Exception report
message

descriptionThe server encountered an internal error () that prevented it from fulfilling this request.
exception
java.lang.IllegalStateException: Imbalanced frame stack! (exit() called too many times)
com.springsource.insight.intercept.trace.ThreadLocalFrameBuilder.exit(ThreadLocalFrameBuilder.java:61)
com.springsource.insight.collection.DefaultOperationCollector.exit(DefaultOperationCollector.java:111)
com.springsource.insight.collection.DefaultOperationCollector.exitAbnormal(DefaultOperationCollector.java:85)
com.springsource.insight.plugin.annotation.InsightOperationAnnotationCollectionAspect.ajc$afterThrowing$com_springsource_insight_plugin_annotation_InsightOperationAnnotationCollectionAspect$3$5840edd2(InsightOperationAnnotationCollectionAspect.aj:50)
com.concur.midtier.webservices.xmlhttp.servlets.ReqRespMessageListener.service(ReqRespMessageListener.java:165)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

note The full stack trace of the root cause is available in the VMware vFabric tc Runtime 2.6.2.RELEASE/7.0.22.A.RELEASE logs.

There are few options to resolve this issue.

1. Increase the max heap
   For example: -Xmx512m
2. or max PermGen size JVM option.
   For example: -XX:MaxPermSize=256m
3. Increase the Spring insight max frame
   For example: -Dinsight-max-frames=6000

OR you can have all of the above JVM parameters.

Schema Spy, A Graphical Database Schema Metadata Browser.

Schemaspy is a java based tool that analyzes the metadata of a schema in a database and generated the visual representation of it. The output is highly user friendly. You can browse through table via child and parent table relationship.

Schema Spy uses the dot executable from graphviz to generate the graphical representation of the schema and its relationship. Graphviz is the graphics visualization software that takes descriptions of graphs in a simple text language, and make diagrams in several useful formats such as images and SVG for web pages, Postscript for inclusion in PDF or other documents; or display in an interactive graph browser.

Following is the steps to execute the SchemaSpy tool (for a sample MYSQL database.)
1. Download and install Graphviz from http://www.graphviz.org/Download..php
2. Download the Schema spay jar file, Schemaspy_x_y_z.jar from http://sourceforge.net/projects/schemaspy/files/
3. Download the corresponding JDBC Connector and have it on the same source folder where the schemaspy_x_y_z.jar resides. For example for a mysql database, I would simply download mysql-connector-java-5.1.5.jar or any other latest version of mysql connector.
4. Now from the source location of your Schemaspy_x_y_z.jar file, execute schemaspy to generate the graphical representation of the schema of your database, as shown on the following syntax

java -jar schemaSpy_x.y.z.jar -t database_type -dp mysql jdbcdatabase_connector -hq -o output_Directory -db databaseName -u username -p password
for example : java -jar schemaSpy_4.1.1.jar -t mysql -dp mysql-connector-java-5.1.5.jar -hq -o out -db bisudatabae -u bishow -p north


Converting Clob Datatype to String and ViceVersa .

If you have been using Hibernate 3.x.x or greater you can easily convert clob type to string type and vice versa, i.e String data type to Clob type.

Following piece of codes demonstrate the process of doing the conversion.


.........
.........

Clob textClobValue;
String textValue;
String newTextValue;
Clob newTextClobValue;
InputStream textStream;
Paragraph paragraph // my domain Class that contains a clob datatypes and used to update the database connection with hibernate connection (Hibernate version >=3.0)
...........
...........

textClobValue=paragraph.getText();
textStream = textClobValue.getAsciiStream(); //return inputstream
textValue=convertStreamToString(textStream);
newTextValue=textValue.replaceAll("Some text","new Text"); //Replacing some text from old text.

newTextClobValue=Hibernate.createClob(newTextValue);
//System.out.println("Updated="+newParaContentValue);
paragraph.setText(newTextClobValue);
..........
..........
..........



public static String convertStreamToString(InputStream is) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;

while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
return sb.toString();
}



Reading the status code of HTTP Request !

When you make an HTTP request to any server url throuh your client software, lets say IE, HTTP Status codes are returned by the server to the client software to determine the outcome of your request. There are five different classes of status code range. They are
Status codes 100-101
Status codes 200-206
Status codes 300-307
Status codes 400-417
Status codes 500-505

Following is a simple program written in groovy that checks and returns the status code of any url.

import java.net.URL;
def url
def message =""
boolean fail=true
def urlString="http://192.168.0.1/test/test.html"
println checkURL(urlString)

def checkURL(urlString){
int status_code
def tempmessage=""
URL URLserver = new URL("urlString");
try{
URLConnection connection = (HttpURLConnection)URLserver.openConnection();

status_code = connection.getResponseCode();


switch (status_code)
{
case 200:
tempmessage=" Connection Successful"
break;
case 401:
tempmessage="UnAuthorised"
break;
case 405 :
tempmessage= " Resource Not Found"
break;
case 408:
tempmessage="Request Time-out"
break;
case 500:
tempmessage="Internal Server Error"
break;
case 502:
tempmessage="Bad Gateway"
break;
case 503:
tempmessage="Service Temporarily Unavailable"
break;
default :
tempmessage= connection.getResponseMessage()
break;

}
}
catch (Exception exc){
tempmessage=exc

}

return "\n "+urlString+" :"+status_code+":"+tempmessage;

}




Visit http://www.w3.org/Protocols/HTTP/HTRESP.html for detail about the status codes.