This extends 15 Apache Spark best practices & performance tuning interview FAQs to delve into DAGs, Stages, Tasks, Partitions and Shuffling in Spark. If you can’t read Spark Event Timelines & DAGs, you will be running blind as to how efficient your code is. … Read more ›...
Q1. What is Splunk and where will you use it?
A1. Splunk is an enterprise-grade software tool for collecting and analyzing “machine data” like log files, feed files, and other big data in terra bytes. You can upload logs from your websites and let Splunk index them,
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This extends Spring Boot annotations interview Q&As and Java exception handling interview questions and answers. Q01. What is exception handling & why is it important? A01. In Java, Exceptions are objects that are thrown when an error or unexpected situation occurs during the execution of a program. … Read more...
Spring security pre-authentication scenario assumes that a valid authenticated user is available via either Single Sign On (SSO) applications like Siteminder, Tivoli, etc or a X509 certification based authentication. The Spring security in this scenario will only be used for authorization.
The example shown below retrieves the user name via the HTTP headers.
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This extedns configuring JDBC and JPA to configure the TransactionManager.
Example #1 Wiring JDBC Transaction Manager
Note: @EnableTransactionManagement annotation
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@Configuration @ImportResource("application.yml") @EnableTransactionManagement public class AppConfig @Bean public DriverManagerDataSource datasource() { DriverManagerDataSource ds = new DriverManagerDataSource(); ds.setDriverClassName(environment.getRequiredProperty("spring.datasource.driver-class-name")); ds.setUrl(environment.getRequiredProperty("spring.datasource.url")); ds.setUsername(environment.getRequiredProperty("spring.datasource.username")); ds.setPassword(environment.getRequiredProperty("spring.datasource.password")); return ds; } @Bean public JdbcTemplate jdbcTemplate() { return new JdbcTemplate(datasource()); } @Bean public DataSourceTransactionManager transactionManager() { final DataSourceTransactionManager transactionManager = new DataSourceTransactionManager(datasource()); return transactionManager; } } |
If you want to create a mock transaction manager, then you can do
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package sample; import org.springframework.stereotype.Service; import org.springframework.transaction.PlatformTransactionManager; import org.springframework.transaction.TransactionDefinition; import org.springframework.transaction.TransactionException; import org.springframework.transaction.TransactionStatus; public class MockedTransactionManager implements PlatformTransactionManager { @Override public TransactionStatus getTransaction(TransactionDefinition definition) throws TransactionException { return null; } @Override public void commit(TransactionStatus status) throws TransactionException { } @Override public void rollback(TransactionStatus status) throws TransactionException { } } |
Also,
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Q1. What is wrong with SQLException? A1. When a SQLException occurs, you do not necessarily know what went wrong. It could be a temporary failure that correct itself with time like a database deadlock or rebooting server OR a permanent fault like bad SQL or missing columns in a table...
Q. What do you understand by the terms trusstores and keystores in Java? A. You generally need a truststore that points to a file containing trusted certificates, no matter whether you are implementing the server or the client side. … Read more ›...
Step 1: Create public-private key pair: Using keytool utility, which is packaged in %JAVA_HOME%/bin/keytool.exe you can create “public-private” key-pair. This means the public and private keys are mathematically related so that encrypting with one key can be decrypted with the other key,
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Large mission critical applications use Straight Through Processing, and these systems need to be highly scalable. So, when you apply for these high paying jobs, it really pays to prepare for your job interviews with the following questions and answers.
Q. What is Straight Through Processing (STP)?
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This extends Why do Proxy, Decorator, Adapter, Bridge, and Facade design patterns look similar? What are the differences? Strategy Vs State design patterns Both the strategy & state design patterns are similar, and the UML diagrams look the same, but the intent for both patterns are different. … Read more...
Cause #1: The JVM spends more time performing garbage collection due to improper Garbage Collection (GC) configuration. E.g. Young generation being too small. Heap size is too small (use -Xmx). The application footprint is larger than the allocated heap size. … Read more ›...
1. CTRL+1
Probably the most useful one. It activates the quick fix and generates lots of code for you. This means less typing.
Generating local variables: For example, if you have written a method call and you highlight it and press Ctrl+1,
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#1: ConcurrentModificationException Getting a ConcurrentModificationException when trying to modify (i.e. adding or removing an item) a collection while iterating. The following code throws a ConcurrentModificationException.
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List<T> list = getListOfItems(); for (Iterator<T> iter = list.iterator(); iter.hasNext(); ) { T obj = iter.next(); if (obj.someCondition()) { list.remove(0); // ConcurrentModificationException } } |
To avoid ConcurrentModificationException in a single-threaded environment, you can remove the object that you are working on with the iterator. … Read more ›...
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