The following code sample would not throw the expected IAE:

import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Base64;

public class NowhereToWrite {
    public static void main(String[] args) {
        Base64.getDecoder().decode(
                ByteBuffer.wrap("bGV==h==c3VyZS4=".getBytes(StandardCharsets.US_ASCII)),
                ByteBuffer.allocate(0));
    }
}


The following testcases will fail due to this issue:


api/java_util/Base64/Decoder/index.html#DecodingNonValidBase64Scheme_MIME[decodeBufferInvalidBase64_nowhereToWrite_emptyByteBuffer]
api/java_util/Base64/Decoder/index.html#DecodingNonValidBase64Scheme_MIME[decodeBufferInvalidBase64_nowhereToWrite_fullByteBuffer]
api/java_util/Base64/Decoder/index.html#DecodingNonValidBase64Scheme_Basic[decodeBufferInvalidBase64_nowhereToWrite_emptyByteBuffer]
api/java_util/Base64/Decoder/index.html#DecodingNonValidBase64Scheme_Basic[decodeBufferInvalidBase64_nowhereToWrite_fullByteBuffer]
api/java_util/Base64/Decoder/index.html#DecodingNonValidBase64Scheme_URL[decodeBufferInvalidBase64_nowhereToWrite_emptyByteBuffer]
api/java_util/Base64/Decoder/index.html#DecodingNonValidBase64Scheme_URL[decodeBufferInvalidBase64_nowhereToWrite_fullByteBuffer]