Entries by tag: jvm

Including child/synonym tags

Spark dataframe Examples: Reading and Writing Dataframes  23 Feb 2020    spark scala
Some examples on how to read and write spark dataframes from sources such as S3 and databricks file systems. Read More ›

Spark SQL Case/When Examples  09 Nov 2019    spark
Case/when clauses are useful to mimic if/else behaviour in SQL and also spark, via when/otherwise clauses. Read More ›

Spark Date/Datetime Functions: Examples  09 Nov 2019    spark scala
Examples on how to use spark date and datetime functions for commonly used transformations. Read More ›

Spark Dataframe Examples: Window Functions  22 Aug 2019    spark dataframes scala
Examples on how to do common operations using window functions in apache spark dataframes. Examples using the Spark Scala API. Read More ›

Spark Dataframe Examples: Pivot and Unpivot Data  10 Aug 2019    spark scala
Pivoting and unpivoting are very commonly-used data transformation operations. Use them when you want to switch from a row-based to a column-based view and vice-versa. Read More ›

Jupyter Notebook Kernels: How to Add, Change, Remove  28 Jul 2019    jupyter-notebooks scala spark
Add, remove and change Kernels to use with Jupyter notebook Read More ›

Corda Framework Overview + Examples  07 Apr 2018    dlt jvm
Overview of the main concepts of the Corda framework for building decentralized applications based on Distributed Ledger Technology (DLT). Read More ›

Scala Testing with Scalatest: Reference and Examples  06 Jul 2017    testing scala
Simple examples using ScalaTest to test your Scala projects. Full introduction and examples of all major testing styles supported by this framework. Read More ›

Debugging NullPointerException in Apache Spark  04 Jun 2017    spark nullpointerexception
A lot of things can go wrong when writing distributed code in Spark. Here's a couple of ways to work around/debug NullPointerExceptions. Read More ›

Spark Concepts Overview: Clusters, Jobs, Stages, Tasks, etc  03 Jan 2017    spark architecture
Spark Streaming: Commong Pitfalls and Tips for Long-running Streaming Applications  11 Dec 2016    spark-streaming
Running Spark Streaming applications may introduce a couple of problems that you may not face when you are running Spark on Batch mode. Here are a couple of things you may need to take into account to keep long-running spark streaming jobs running smoothly. Read More ›

ApplicationAttemptNotFoundException: Spark Application Stuck in ACCEPTED state on YARN  13 Nov 2016    emr yarn spark
ApplicationAttemptNotFoundException may be cause because the log directory have become too crowded with data. Read More ›

Akka-http Common Operations: Reference + Examples  03 Nov 2016    akka-http akka wip
A couple of things I find myself doing very often when I use akka-http. I believe these may be useful for others too. Read More ›

Publishing an SBT Project onto Bintray: an Example  20 Aug 2016    sbt bintray
A quick example explaining everything you need to do to package an SBT project and publish the binary JAR to bintray, where it can be made available for others too! Read More ›

Add a Github Project as a Dependency in SBT  13 Aug 2016    sbt
Small example on how to quickly add a project you found on github to your own project as a dependency. Read More ›

Packaging an Akka-http Application using SBT and Docker: Simple Example  29 Jun 2016    docker akka-http sbt
A simple example displaying common akka-http use cases and a couple of tips and hints to guide you through packaging a full app as a Docker container, so that you can deploy it anywhere you want. Read More ›

Migrating a Project from Spray to Akka-http: General Tips and Reference  29 May 2016    akka-http spray scala wip
Troublesshooting Akka: ClassNotFoundException: akka.event.slf4j.Slf4jLoggingFilter  19 May 2016    akka slf4j scala
Java.time API: Examples and Reference  01 Apr 2016    java 8 datetime scala
Using the AWS CLI to manage Spark Clusters on EMR: Examples and Reference  23 Mar 2016    emr cli wip spark
Update Java to JDK 8 on Amazon Elastic MapReduce  22 Mar 2016    emr spark java 8
Comparing Interactive Solutions for Running Scala and Spark: Zeppelin, Spark-notebook and Jupyter-scala  07 Mar 2016    notebook interactive scala spark zeppelin
Json4s Examples: Common Basic Operations using Jackson as Backend  29 Feb 2016    json scala json4s
Json4s is one of the best libraries for manipulating json in Scala. Here are some examples and common use cases you may have come across and some you perhaps haven't. Read More ›

Apache Zeppelin, Spark Streaming and Amazon Kinesis: Simple Guide and Examples  19 Feb 2016    emr spark zeppelin kinesis wip
Fully Customized Json Validators for the Play 2 Framework: Explanation and Example  05 Jan 2016    play 2 json
Play 2 Allows a lot of flexibility for defining custom rules for JSON validation but if you want full control over how JSON is validated against a case class (including conditions that depend on more than one attribute and custom error messages) you need to write custom readers for your classes. Read More ›

JVM Performance Monitoring 101: Commonly Used Open Source Tools + Examples  28 Dec 2015    jvm java scala java 8 wip
Performance monitoring is an essential part of the work of whoever works on the JVM using not just java but other JVM languages such as Scala, Groovy and Clojure. Here are some of the most widely-used open-source tools with examples, so that you can do your work more easily. Read More ›

Java 8 Timezones: Examples in Scala  23 Dec 2015    java 8 datetime
Many Scala examples of the new Java 8 `java.time` API, focusing on ways to deal with and encode Timezone information in your objects. Read More ›

Spark DataFrame UDFs: Examples using Scala and Python  11 Nov 2015    spark udf wip
Add an Apache Zeppelin UI to your Spark cluster on AWS EMR  10 Nov 2015    aws emr spark zeppelin wip
Creating a Spark Cluster on AWS EMR: a Tutorial  10 Nov 2015    aws emr spark
AWS now provides full support for Spark Clusters within Elastic MapReduce (EMR). It's very simples and you just need a couple of minutes to learn how to do it. Read More ›

Creating Scala Fat Jars for Spark on SBT with sbt-assembly Plugin  18 Sep 2015    sbt hadoop spark sbt-assembly
Spark-submit: Examples and Reference  13 Sep 2015    spark scala
Deadbolt 2 for the Play Framework in Scala: Defining a custom Handler  02 Sep 2015    deadbolt play play 2 authorization
Slick 3 Reference and Examples  18 Jun 2015    slick 3 slick scala orm frm
Attaching Sources to a Scala Project on IDEA Intellij  24 Apr 2015    scala idea intellij
Play 2 Framework with Scala: Complex JSON Validator Examples  09 Mar 2015    scala play2 json forms validation
Scala Slick: Simple Example on Connecting to a PostgreSQL Database  14 Jan 2015    slick postgres
Slick DB Sessions in Play 2 Framework for Scala  03 Dec 2014    scala implicit slick database
Performance Tips for Scala IDE for Eclipse  25 Nov 2014    performance eclipse scala
Slick 2 Examples: Querying and Modifying Data  20 Nov 2014    slick scala
Scala Goodies: Pattern matching with typed lists or Working around Scala's type erasure  06 Nov 2014    scala types
Scala Imports: Quick Intro and Examples  03 Nov 2014    scala import
Scala Examples - Sorting Lists and other Collections in Scala  26 Oct 2014    scala lists ordering
Templates for Slick Domain Classes mapping to DB Tables  21 Oct 2014    slick
Scala Slick: Dealing with Datetime/Timestamp Attributes  10 Oct 2014    scala slick database orm frm datetime
Play-slick Plugin Error Message: NoClassDefFoundError: org/reflections/scanners/TypesScanner  09 Oct 2014    slick error play2
Working with JSON data on the Play Framework for Scala: Examples  09 Oct 2014    scala json play
Scala Futures: simple Explanation with Examples  07 Oct 2014    scala future wip
Slick Error Message: 'value tupled is not a member of object'  30 Sep 2014    slick scala play
Play2 Scala: Forms and Validations  19 Sep 2014    scala forms play-framework
Scala Functions: Examples and Reference  14 Sep 2014    scala functions syntax
Scala Regular Expressions: Examples & Reference  08 Sep 2014    scala regular-expressions string
Querying an Elasticsearch Server using Scala  15 Jul 2014    elasticsearch scala