/usr/share/doc/openjdk-9-jre-headless/examples/lambda/ is in openjdk-9-demo 9~b114-0ubuntu1.
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/usr/share/doc/openjdk-9-jre-headless/examples/lambda/BulkDataOperations/
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/BulkDataOperations/index.html
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/BulkDataOperations/src/
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/BulkDataOperations/src/CSVProcessor.java
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/BulkDataOperations/src/Grep.java
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/BulkDataOperations/src/PasswordGenerator.java
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/BulkDataOperations/src/WC.java
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/DefaultMethods/
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/DefaultMethods/ArrayIterator.java
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/DefaultMethods/DiamondInheritance.java
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/DefaultMethods/Inheritance.java
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/DefaultMethods/MixIn.java
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/DefaultMethods/Reflection.java
/usr/share/doc/openjdk-9-jre-headless/examples/lambda/DefaultMethods/SimplestUsage.java