grep
grep “hello” *.csv zgrep “hello” *.csv.gz
Credit card jargon
PAN – the card number BIN – the first 6 digits of the card number, which identifies the issuer of the card CVV – It is on the back of your card. Normally it has 3 digits. Providing your CVV number to an online merchant proves that you actually have the physical credit or …
Library dependency V.S. Remote API dependency in SOA
Pros of Library Dependency: Simplicity in terms of implementation. In java, all you need is Maven. There is no need for any RPC serialiser or RPC middleware. Simplicity in terms of deployment. You will need less applications than the RPC approach. Each application requires investment of auto-deployment, monitoring, hardware resources, and load balancing in some …
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Scrum is good at time management
Scrum is good at time management because it puts every activity under track without any exceptions. All what you are doing should be tasks on the white board. Requirement analysis, tech design are now grooming sessions and spikes. They are all scrum terms and will be handled in a formal way so time spent …
You can have small grooming sessions instead of a big one
You don’t have to have a big grooming session to analyse all the user stories for next sprint. That will be tiresome since it takes long, and people won’t like it. Instead you can break them into small ones, like a one-hour session everyday for a few days while you are still going on …
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Tomcat gets stuck during start up?
It takes more than 5 minutes for your tomcat to startup. You think it’s your application’s program. But when you download a clean Tomcat (of the same version) can run it without dropping in any of your applications, it still gets stuck. It may be caused by this: https://wiki.apache.org/tomcat/HowTo/FasterStartUp#Entropy_Source According to my just wasted 2 …
Call Java compiler programatically
You don’t need to add any dependency private static void doCompile(File sourceDir) throws SomeException { System.out.println(“Compiling started”); JavaCompiler compiler = ToolProvider.getSystemJavaCompiler(); DiagnosticCollector diagnostics = new DiagnosticCollector(); StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnostics, null, null); Collection files = FileUtils.listFiles(sourceDir, new String[] { “java” }, true); Iterable compilationUnits = fileManager.getJavaFileObjectsFromFiles(files); List compilerOptions = Arrays.asList(“-source”, “1.6”, “-target”, “1.6”); JavaCompiler.CompilationTask task …
javax.xml.ws.Endpoint cannot publish multiple endpoints in a single network address
This will work: Endpoint.publish(“http://localhost:9999/ws/order”, new OrderPortImpl()); But this won’t: Endpoint.publish(“http://localhost:9999/ws/order”, new OrderPortImpl()); Endpoint.publish(“http://localhost:9999/ws/product”, new ProductPortImpl()); In the latter case, you will see java.net.BindException: Address already in use
Tips for traversing a tree with stacks
Here are the tips of my solution: You always push the root to the stack first The most difficult part is: when you see a node on the top of element, should you go on to push its children, or pop it to print it? For pre-order traversal, you can pop it then push …
Propagate data change from RDBMS to Solr
Basically, you will use solr’s DataImportHandler to do the importing. Hit http://solr-server:port/solr/db/dataimport?command=full-import to do a full import. Hit http://solr-server:port/solr/dataimport?command=delta-import to do a delta import So, what’s the delta? This is configured in some data-config.xml: deltaQuery=”select id from item where last_modified > ‘${dih.last_index_time}'” So it requires the table on your database must have a column called …