This is snipper of my ANTLR grammar for parsing expressions with operator precedence, By default the expressions are evaluated left to right which in some cases may produce undesired results, in order to fix that use of left and right parenthesis is required. For example this two expressions will be evaluated differently 3 > 2 …
Simply adding @Transactional on the method will resolve this issue
Other day I needed to convert excel spreadsheet column name to column index when having 200+ columns is easier to express as ‘FB’ instead of 157 A = 0 B = 1 AA = 26 AA = 27 FB = 157 This code will work for any number of column names. /** * Convert given …
Convert given excel column name to column Index, ex ‘A=0’, ‘AA=26’ Read More »
The other day I needed to read output stream directly into a string, but JDK does not provides us with a stream directly for that. There have been numerous discussions on why and why not we should have this build into the JDK, but this was a case where I did need it and knew …
StringOutputStream backed by ByteArrayOutputStream Read More »
Detecting Wide Area Network(WAN) IP programmatically This is a reliable way to detect WAN IP address from Java, cpp or any other programming language. Motivation for this was my need to update my DNS server automatically, presented code will be in Java I have decided to use Java for cross-platform support and its my favorite …
Detecting Wide Area Network(WAN) IP programmatically Read More »
While upgrading machines I have upgraded to run jdk 1.6 which have screwed up compiling of my reports with following error. C:\Program Files (x86)\Java\jdk1.6.0_24\jre\lib\endorsed Source File:c:/Users/greg/report2.jrxml Exception in thread "main" net.sf.jasperreports.engine.JRRuntimeException: Error creating SAX parser at net.sf.jasperreports.engine.xml.JRReportSaxParserFactory.createParser(JRReportSaxParserFactory.java:109) at net.sf.jasperreports.engine.xml.JRXmlDigesterFactory.createParser(JRXmlDigesterFactory.java:1320) at net.sf.jasperreports.engine.xml.JRXmlDigesterFactory.createDigester(JRXmlDigesterFactory.java:1295) at net.sf.jasperreports.engine.xml.JRXmlLoader.load(JRXmlLoader.java:199) at net.sf.jasperreports.engine.xml.JRXmlLoader.load(JRXmlLoader.java:164) at net.sf.jasperreports.engine.xml.JRXmlLoader.load(JRXmlLoader.java:148) at net.sf.jasperreports.engine.JasperCompileManager.compileReportToFile(JasperCompileManager.java:85) at com.americanbanksystems.complianceproreports.util.CompileReport.compileReport(CompileReport.java:133) at com.americanbanksystems.complianceproreports.util.CompileReport.main(CompileReport.java:189) Caused by: …
While starting Nexus I was getting following error, this was on a machine that was running at 1GB of memory. Error occurred during initialization of VM Could not reserve enough space for object heap So the solution was to edit /usr/local/nexus/bin/jws/wrapper.conf and add wrapper.java.additional.4=-Xmx128m parameter this setup java to use only 128mb of memory for …
This is one way of creating a group by like functionality for collections using google guava Multimap and Function. Code is straight forward we simply use the index method of the Multimap to group our data by, in here we use our 2 column to group it by the department. Sample output key = Dev …
Implementing GroupBy using Google guava Multimap and Function Read More »
This is my helper method for invoking webservices from java. One bonus perk is that this handles the exception when we are using self signed certificates by providing our own HostnameVerifier. This could be more generalized but all I needed was to invoke this one server. /** * Invoke webservice to retrive data * * …
This code will detach a entity from hibernate Entitymanger making it thus unmanaged entity. // Prepare workbook object to be used for cloning. Session session = (Session) entityManager.getDelegate(); session.evict(workbook); // same as detached workbook.setId(null);// Prepare workbook object to be used for cloning. Session session = (Session) entityManager.getDelegate(); session.evict(workbook); // same as detached workbook.setId(null);
