Mixing
Why does an incomplete switch expression compile successfully
Trying out JDK/12 EarlyAccess Build 20, where the JEP-325 Switch Expressions has been integrated as a preview feature. A sample code for the expressions (as in the JEP as well):
Scanner scanner = new Scanner(System.in);
Day day = Day.valueOf(scanner.next().toUpperCase());
int i = switch (day) {
case MONDAY,TUESDAY, WEDNESDAY:
break 0;
default:
System.out.println("Second half of the week");
// ERROR! Group doesn't contain a break with value
};
I was trying to follow the same procedure as stated in a previous question on how to Compile a JDK12 preview feature with Maven and execute the above block of code using the command line:
java --enable-preview -jar target/jdk12-updates-1.0.0-SNAPSHOT.jar
Somewhat to my expectation I got the following error :
Error: Unable to initialize main class
com.stackoverflow.nullpointer.expression.SwitchExpressionMustComplete
Caused by: java.lang.VerifyError: Bad local variable type Exception
Details: Location:
com/stackoverflow/nullpointer/expression/SwitchExpressionMustComplete.main([Ljava/lang/String;)V @66: iload
Reason:
Type top (current frame, locals[4]) is not assignable to integer
Current Frame:
bci: @66
flags: { }
locals: { '[Ljava/lang/String;', 'java/util/Scanner', 'com/stackoverflow/nullpointer/Day' }
stack: { }
Bytecode:
0000000: bb00 0259 b200 03b7 0004 4c2b b600 05b8
0000010: 0006 4db2 0007 2cb6 0008 2eaa 0000 001f
0000020: 0000 0001 0000 0003 0000 0019 0000 0019
0000030: 0000 0019 0336 04a7 000b b200 0912 0ab6
0000040: 000b 1504 3eb1
Stackmap Table:
append_frame(@52,Object[#2],Object[#34])
same_frame(@58)
same_frame(@66)
I am aware that the document points out that the code is erroneous and replacing the comment with break 1; resolves it, but the questions I have are:
Q1. Why does the compile phase succeed for the same? Shouldn't that fail at compile time itself?
Q2. What is the cause that I see such detailed error message? Could the --enable-preview feature responsible for this?
java switch-statement javac java-12 preview-feature
asked Nov 19 '18 at 19:22
nullpointernullpointer
44.2k1095182
add a comment |
Trying out JDK/12 EarlyAccess Build 20, where the JEP-325 Switch Expressions has been integrated as a preview feature. A sample code for the expressions (as in the JEP as well):
Scanner scanner = new Scanner(System.in);
Day day = Day.valueOf(scanner.next().toUpperCase());
int i = switch (day) {
case MONDAY,TUESDAY, WEDNESDAY:
break 0;
default:
System.out.println("Second half of the week");
// ERROR! Group doesn't contain a break with value
};
I was trying to follow the same procedure as stated in a previous question on how to Compile a JDK12 preview feature with Maven and execute the above block of code using the command line:
java --enable-preview -jar target/jdk12-updates-1.0.0-SNAPSHOT.jar
Somewhat to my expectation I got the following error :
Error: Unable to initialize main class
com.stackoverflow.nullpointer.expression.SwitchExpressionMustComplete
Caused by: java.lang.VerifyError: Bad local variable type Exception
Details: Location:
com/stackoverflow/nullpointer/expression/SwitchExpressionMustComplete.main([Ljava/lang/String;)V @66: iload
Reason:
Type top (current frame, locals[4]) is not assignable to integer
Current Frame:
bci: @66
flags: { }
locals: { '[Ljava/lang/String;', 'java/util/Scanner', 'com/stackoverflow/nullpointer/Day' }
stack: { }
Bytecode:
0000000: bb00 0259 b200 03b7 0004 4c2b b600 05b8
0000010: 0006 4db2 0007 2cb6 0008 2eaa 0000 001f
0000020: 0000 0001 0000 0003 0000 0019 0000 0019
0000030: 0000 0019 0336 04a7 000b b200 0912 0ab6
0000040: 000b 1504 3eb1
Stackmap Table:
append_frame(@52,Object[#2],Object[#34])
same_frame(@58)
same_frame(@66)
I am aware that the document points out that the code is erroneous and replacing the comment with break 1; resolves it, but the questions I have are:
Q1. Why does the compile phase succeed for the same? Shouldn't that fail at compile time itself?
Q2. What is the cause that I see such detailed error message? Could the --enable-preview feature responsible for this?
java switch-statement javac java-12 preview-feature
asked Nov 19 '18 at 19:22
nullpointernullpointer
44.2k1095182
add a comment |
Trying out JDK/12 EarlyAccess Build 20, where the JEP-325 Switch Expressions has been integrated as a preview feature. A sample code for the expressions (as in the JEP as well):
Scanner scanner = new Scanner(System.in);
Day day = Day.valueOf(scanner.next().toUpperCase());
int i = switch (day) {
case MONDAY,TUESDAY, WEDNESDAY:
break 0;
default:
System.out.println("Second half of the week");
// ERROR! Group doesn't contain a break with value
};
I was trying to follow the same procedure as stated in a previous question on how to Compile a JDK12 preview feature with Maven and execute the above block of code using the command line:
java --enable-preview -jar target/jdk12-updates-1.0.0-SNAPSHOT.jar
Somewhat to my expectation I got the following error :
Error: Unable to initialize main class
com.stackoverflow.nullpointer.expression.SwitchExpressionMustComplete
Caused by: java.lang.VerifyError: Bad local variable type Exception
Details: Location:
com/stackoverflow/nullpointer/expression/SwitchExpressionMustComplete.main([Ljava/lang/String;)V @66: iload
Reason:
Type top (current frame, locals[4]) is not assignable to integer
Current Frame:
bci: @66
flags: { }
locals: { '[Ljava/lang/String;', 'java/util/Scanner', 'com/stackoverflow/nullpointer/Day' }
stack: { }
Bytecode:
0000000: bb00 0259 b200 03b7 0004 4c2b b600 05b8
0000010: 0006 4db2 0007 2cb6 0008 2eaa 0000 001f
0000020: 0000 0001 0000 0003 0000 0019 0000 0019
0000030: 0000 0019 0336 04a7 000b b200 0912 0ab6
0000040: 000b 1504 3eb1
Stackmap Table:
append_frame(@52,Object[#2],Object[#34])
same_frame(@58)
same_frame(@66)
I am aware that the document points out that the code is erroneous and replacing the comment with break 1; resolves it, but the questions I have are:
Q1. Why does the compile phase succeed for the same? Shouldn't that fail at compile time itself?
Q2. What is the cause that I see such detailed error message? Could the --enable-preview feature responsible for this?
java switch-statement javac java-12 preview-feature
asked Nov 19 '18 at 19:22
nullpointernullpointer
44.2k1095182
Trying out JDK/12 EarlyAccess Build 20, where the JEP-325 Switch Expressions has been integrated as a preview feature. A sample code for the expressions (as in the JEP as well):
Scanner scanner = new Scanner(System.in);
Day day = Day.valueOf(scanner.next().toUpperCase());
int i = switch (day) {
case MONDAY,TUESDAY, WEDNESDAY:
break 0;
default:
System.out.println("Second half of the week");
// ERROR! Group doesn't contain a break with value
};
I was trying to follow the same procedure as stated in a previous question on how to Compile a JDK12 preview feature with Maven and execute the above block of code using the command line:
java --enable-preview -jar target/jdk12-updates-1.0.0-SNAPSHOT.jar
Somewhat to my expectation I got the following error :
Error: Unable to initialize main class
com.stackoverflow.nullpointer.expression.SwitchExpressionMustComplete
Caused by: java.lang.VerifyError: Bad local variable type Exception
Details: Location:
com/stackoverflow/nullpointer/expression/SwitchExpressionMustComplete.main([Ljava/lang/String;)V @66: iload
Reason:
Type top (current frame, locals[4]) is not assignable to integer
Current Frame:
bci: @66
flags: { }
locals: { '[Ljava/lang/String;', 'java/util/Scanner', 'com/stackoverflow/nullpointer/Day' }
stack: { }
Bytecode:
0000000: bb00 0259 b200 03b7 0004 4c2b b600 05b8
0000010: 0006 4db2 0007 2cb6 0008 2eaa 0000 001f
0000020: 0000 0001 0000 0003 0000 0019 0000 0019
0000030: 0000 0019 0336 04a7 000b b200 0912 0ab6
0000040: 000b 1504 3eb1
Stackmap Table:
append_frame(@52,Object[#2],Object[#34])
same_frame(@58)
same_frame(@66)
I am aware that the document points out that the code is erroneous and replacing the comment with break 1; resolves it, but the questions I have are:
Q1. Why does the compile phase succeed for the same? Shouldn't that fail at compile time itself?
Q2. What is the cause that I see such detailed error message? Could the --enable-preview feature responsible for this?
java switch-statement javac java-12 preview-feature
java switch-statement javac java-12 preview-feature
asked Nov 19 '18 at 19:22
nullpointernullpointer
44.2k1095182
asked Nov 19 '18 at 19:22
nullpointernullpointer
44.2k1095182
asked Nov 19 '18 at 19:22
nullpointernullpointer
44.2k1095182
asked Nov 19 '18 at 19:22
nullpointernullpointer
44.2k1095182
asked Nov 19 '18 at 19:22
nullpointernullpointer
44.2k1095182
44.2k1095182
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
This is a known bug. See
https://bugs.openjdk.java.net/browse/JDK-8212982
for details on its status.
answered Nov 19 '18 at 22:02
Brian GoetzBrian Goetz
56.3k1399115
Well, not sure how these are linked, but on the contrary the code in this bug report actually fails to compile for me with error : or -> expected .... not a statement
– nullpointer
Nov 20 '18 at 1:47
How about the other part of the question, what is the reason that I see such detailed error message? (Not that I am worried about seeing it, just curious to know if I could use some JVM flag to toggle to this view for errors reported.)
– nullpointer
Nov 20 '18 at 3:47
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
This is a known bug. See
https://bugs.openjdk.java.net/browse/JDK-8212982
for details on its status.
answered Nov 19 '18 at 22:02
Brian GoetzBrian Goetz
56.3k1399115
Well, not sure how these are linked, but on the contrary the code in this bug report actually fails to compile for me with error : or -> expected .... not a statement
– nullpointer
Nov 20 '18 at 1:47
How about the other part of the question, what is the reason that I see such detailed error message? (Not that I am worried about seeing it, just curious to know if I could use some JVM flag to toggle to this view for errors reported.)
– nullpointer
Nov 20 '18 at 3:47
add a comment |
This is a known bug. See
https://bugs.openjdk.java.net/browse/JDK-8212982
for details on its status.
answered Nov 19 '18 at 22:02
Brian GoetzBrian Goetz
56.3k1399115
Well, not sure how these are linked, but on the contrary the code in this bug report actually fails to compile for me with error : or -> expected .... not a statement
– nullpointer
Nov 20 '18 at 1:47
How about the other part of the question, what is the reason that I see such detailed error message? (Not that I am worried about seeing it, just curious to know if I could use some JVM flag to toggle to this view for errors reported.)
– nullpointer
Nov 20 '18 at 3:47
add a comment |
This is a known bug. See
https://bugs.openjdk.java.net/browse/JDK-8212982
for details on its status.
answered Nov 19 '18 at 22:02
Brian GoetzBrian Goetz
56.3k1399115
This is a known bug. See
https://bugs.openjdk.java.net/browse/JDK-8212982
for details on its status.
answered Nov 19 '18 at 22:02
Brian GoetzBrian Goetz
56.3k1399115
answered Nov 19 '18 at 22:02
Brian GoetzBrian Goetz
56.3k1399115
answered Nov 19 '18 at 22:02
Brian GoetzBrian Goetz
56.3k1399115
answered Nov 19 '18 at 22:02
Brian GoetzBrian Goetz
56.3k1399115
56.3k1399115
Well, not sure how these are linked, but on the contrary the code in this bug report actually fails to compile for me with error : or -> expected .... not a statement
– nullpointer
Nov 20 '18 at 1:47
How about the other part of the question, what is the reason that I see such detailed error message? (Not that I am worried about seeing it, just curious to know if I could use some JVM flag to toggle to this view for errors reported.)
– nullpointer
Nov 20 '18 at 3:47
add a comment |
Well, not sure how these are linked, but on the contrary the code in this bug report actually fails to compile for me with error : or -> expected .... not a statement
– nullpointer
Nov 20 '18 at 1:47
How about the other part of the question, what is the reason that I see such detailed error message? (Not that I am worried about seeing it, just curious to know if I could use some JVM flag to toggle to this view for errors reported.)
– nullpointer
Nov 20 '18 at 3:47
Well, not sure how these are linked, but on the contrary the code in this bug report actually fails to compile for me with error : or -> expected .... not a statement
– nullpointer
Nov 20 '18 at 1:47
Well, not sure how these are linked, but on the contrary the code in this bug report actually fails to compile for me with error : or -> expected .... not a statement
– nullpointer
Nov 20 '18 at 1:47
How about the other part of the question, what is the reason that I see such detailed error message? (Not that I am worried about seeing it, just curious to know if I could use some JVM flag to toggle to this view for errors reported.)
– nullpointer
Nov 20 '18 at 3:47
How about the other part of the question, what is the reason that I see such detailed error message? (Not that I am worried about seeing it, just curious to know if I could use some JVM flag to toggle to this view for errors reported.)
– nullpointer
Nov 20 '18 at 3:47
add a comment |
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