Java example source code file (WrongLNTForLambdaTest.java)

This example Java source code file (WrongLNTForLambdaTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

classfile, code_attribute, exception, expected, foo, found, linenumbertable, linenumbertable_attribute, lnt, method, string, the, wronglntforlambdatest

The WrongLNTForLambdaTest.java Java example source code

/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @bug 8019486 8026861 8027142
 * @summary javac, generates erroneous LVT for a test case with lambda code
 * @library /tools/javac/lib
 * @build ToolBox
 * @run main WrongLNTForLambdaTest
 */

import java.io.File;
import java.nio.file.Paths;

import com.sun.tools.classfile.ClassFile;
import com.sun.tools.classfile.Code_attribute;
import com.sun.tools.classfile.LineNumberTable_attribute;
import com.sun.tools.classfile.Method;
import com.sun.tools.javac.util.Assert;

public class WrongLNTForLambdaTest {

    static final String testSource =
    /* 01 */        "import java.util.List;\n" +
    /* 02 */        "import java.util.Arrays;\n" +
    /* 03 */        "import java.util.stream.Collectors;\n" +
    /* 04 */        "\n" +
    /* 05 */        "public class Foo {\n" +
    /* 06 */        "    void bar(int value) {\n" +
    /* 07 */        "        final List<Integer> numbers = Arrays.asList(1, 2, 3);\n" +
    /* 08 */        "        final List<Integer> numbersPlusOne = \n" +
    /* 09 */        "             numbers.stream().map(number -> number / 1).collect(Collectors.toList());\n" +
    /* 10 */        "    }\n" +
    /* 11 */        "    void variablesInLambdas(int value) {\n" +
    /* 12 */        "        Runnable r1 = () -> {\n" +
    /* 13 */        "            int i  = value;\n" +
    /* 14 */        "            class FooBar<T extends CharSequence> {\n" +
    /* 15 */        "                public void run() {\n" +
    /* 16 */        "                    T t = null;\n" +
    /* 17 */        "                }\n" +
    /* 18 */        "            }\n" +
    /* 19 */        "        };\n" +
    /* 20 */        "        Runnable r2 = () -> System.err.println(1);\n" +
    /* 21 */        "        Runnable r3 = (Runnable & java.io.Serializable) this::foo;\n" +
    /* 22 */        "        Runnable r4 = super :: notify;\n" +
    /* 23 */        "    }\n" +
    /* 24 */        "    private void foo() {}\n" +
    /* 25 */        "    void assignLambda() {\n" +
    /* 26 */        "        Runnable r = () -> { };\n" +
    /* 27 */        "    }\n" +
    /* 28 */        "    void callLambda(int i, Runnable r) {\n" +
    /* 29 */        "        callLambda(0,\n" +
    /* 30 */        "                   () -> { });\n" +
    /* 31 */        "    }\n" +
    /* 32 */        "}";

    static final int[][] simpleLambdaExpectedLNT = {
    //  {line-number, start-pc},
        {9,           0},       //number -> number / 1
    };

    static final int[][] lambdaWithVarsExpectedLNT = {
    //  {line-number, start-pc},
        {13,           0},       //number -> number / 1
        {19,           2},       //number -> number / 1
    };

    static final int[][] insideLambdaWithVarsExpectedLNT = {
    //  {line-number, start-pc},
        {16,           0},       //number -> number / 1
        {17,           2},       //number -> number / 1
    };

    static final int[][] lambdaVoid2VoidExpectedLNT = {
    //  {line-number, start-pc},
        {20,           0},       //number -> number / 1
    };

    static final int[][] deserializeExpectedLNT = {
    //  {line-number, start-pc},
        {05,           0},       //number -> number / 1
    };

    static final int[][] lambdaBridgeExpectedLNT = {
    //  {line-number, start-pc},
        {22,           0},       //number -> number / 1
    };

    static final int[][] assignmentExpectedLNT = {
    //  {line-number, start-pc},
        {26,           0},       //number -> number / 1
        {27,           6},       //number -> number / 1
    };

    static final int[][] callExpectedLNT = {
    //  {line-number, start-pc},
        {29,           0},       //number -> number / 1
        {31,           10},       //number -> number / 1
    };

    public static void main(String[] args) throws Exception {
        new WrongLNTForLambdaTest().run();
    }

    void run() throws Exception {
        compileTestClass();
        checkClassFile(new File(Paths.get(System.getProperty("user.dir"),
                "Foo.class").toUri()), "lambda$bar$0", simpleLambdaExpectedLNT);
        checkClassFile(new File(Paths.get(System.getProperty("user.dir"),
                "Foo.class").toUri()), "lambda$variablesInLambdas$1", lambdaWithVarsExpectedLNT);
        checkClassFile(new File(Paths.get(System.getProperty("user.dir"),
                "Foo$1FooBar.class").toUri()), "run", insideLambdaWithVarsExpectedLNT);
        checkClassFile(new File(Paths.get(System.getProperty("user.dir"),
                "Foo.class").toUri()), "lambda$variablesInLambdas$2", lambdaVoid2VoidExpectedLNT);
        checkClassFile(new File(Paths.get(System.getProperty("user.dir"),
                "Foo.class").toUri()), "$deserializeLambda$", deserializeExpectedLNT);
        checkClassFile(new File(Paths.get(System.getProperty("user.dir"),
                "Foo.class").toUri()), "lambda$MR$variablesInLambdas$notify$8bc4f5bd$1", lambdaBridgeExpectedLNT);
        checkClassFile(new File(Paths.get(System.getProperty("user.dir"),
                "Foo.class").toUri()), "assignLambda", assignmentExpectedLNT);
        checkClassFile(new File(Paths.get(System.getProperty("user.dir"),
                "Foo.class").toUri()), "callLambda", callExpectedLNT);
    }

    void compileTestClass() throws Exception {
        ToolBox.JavaToolArgs javacSuccessArgs =
                new ToolBox.JavaToolArgs().setSources(testSource);
        ToolBox.javac(javacSuccessArgs);
    }

    void checkClassFile(final File cfile, String methodToFind, int[][] expectedLNT) throws Exception {
        ClassFile classFile = ClassFile.read(cfile);
        boolean methodFound = false;
        for (Method method : classFile.methods) {
            if (method.getName(classFile.constant_pool).equals(methodToFind)) {
                methodFound = true;
                Code_attribute code = (Code_attribute) method.attributes.get("Code");
                LineNumberTable_attribute lnt =
                        (LineNumberTable_attribute) code.attributes.get("LineNumberTable");
                Assert.check(lnt.line_number_table_length == expectedLNT.length,
                        "The LineNumberTable found has a length different to the expected one");
                int i = 0;
                for (LineNumberTable_attribute.Entry entry: lnt.line_number_table) {
                    Assert.check(entry.line_number == expectedLNT[i][0] &&
                            entry.start_pc == expectedLNT[i][1],
                            "LNT entry at pos " + i + " differ from expected." +
                            "Found " + entry.line_number + ":" + entry.start_pc +
                            ". Expected " + expectedLNT[i][0] + ":" + expectedLNT[i][1]);
                    i++;
                }
            }
        }
        Assert.check(methodFound, "The seek method was not found");
    }

    void error(String msg) {
        throw new AssertionError(msg);
    }

}